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THE CHEMISTRY 



OF 



COOKING AND CLEANING 

A MANUAL FOR HOUSEKEEPERS 

(5 

BY 

ELLEN H. RICHARDS 

AND 

S. MARIA ELLIOTT 




Second EdjT'GN 
Rtvised and Rewritten. 



BOSTON 

HOME SCIENCE PUBLISHING CO. 

1897 



<^ 



0,\ 



\ 



<b 



First Edition. 

Copyright, 1881. 

By Estes & Lauriat. 



■ • 



Second Edition. 

Copyright, 1897. 

By Home Science Publishing Co. 

Si 



PREFACE. 



IN this age of applied science, every opportunity 
of benefiting the household should be seized 
upon. 

The family is the heart of the country's life, and 
every philanthropist or social scientist must begin 
at that point. Whatever, then, will enlighten the 
mind, and lighten the burden of care, of every 
housekeeper will be a boon. 

At the present time, when the electric light and 
the gas stove are familiar topics, there is, after all, 
no branch of science which might be of more 
benefit to the community, if it were properly un- 
derstood, than Chemistry — the Chemistry of Com- 
mon Life. 

There is a space yet unoccupied for an elemen- 
tary work which shall give to non-scientific read- 
ers some practical information as to the chemical 
composition of articles of daily use, and as to their 
action in the various operations in which they are 
employed. 

The public are the more ready for the applica- 
tion of this knowledge since Chemistry is taught 
in nearly all High Schools, and most persons have 
a dim idea of what some part of it means. To 
gather up these indistinct notions into a definite 
and practical form is the aim of this little book. 



iv PREFACE. 

There is, lingering in the air, a great awe of 
chemistry and chemical terms, an inheritance 
from the age of alchemy. Every chemist can re- 
call instances by the score in which manufacturers 
have asked for recipes for making some substitute 
for a well-known article, and have expected the 
most absurd results to follow the simple mixing 
of two substances. Chemicals are supposed by 
the multitude to be all-powerful, and great ad- 
vantage is taken of this credulity by unscrupulous 
manufacturers. 

The number of patent compounds thrown upon 
the market under fanciful and taking names is a 
witness to the apathy of housekeepers. It is time 
that they should bestir themselves for their own 
protection. A little knowledge of the right kind 
cannot hurt them, and it will surely bring a large 
return in comfort and economy. 

These mysterious chemicals are not so many 
or so complicated in structure but that a little 
patient study will enable any one to understand 
the laws of their action, so far as they apply to the 
common operations of the household. 

No attempt is here made to cover the whole 
ground of chemical science, but only to explain 
such of its principles as are involved in the raising 
of bread, and in a few other common processes. 



PREFACE 

To the Second Edition. 



THE science of chemistry has made rapid 
strides in the past fifteen years. Biological 
science has sprung from infancy to sturdy man- 
hood during the same time, and a knowledge of 
both with their relations to each other is necessary 
to the right understanding of the manifold opera- 
tions of life. All the sciences and all the arts are 
taxed by thq intelligent home-maker for the 
proper foundation and continuance of the complex 
life of the home. 

The establishment of more homes and their 
right conduct when established, which results in 
the better utilization of time, money and strength, 
means the perpetuity, prosperity and power of the 
nation. 

Without trespassing upon the domain of house- 
hold bacteriology, a knowledge of the chemistry 
of cooking and cleaning must include some dis- 
cussion of the sources of dirt, its composition and 
its dangers, and the discussion of methods for its 
removal, which shall at the same time be speedy, 
safe and effectual. 



vi PREFACE. 

Experience teaches that in domestic work there 
is no best rule of universal application. Circum- 
stances vary so widely that principles, alone, can 
be laid down. Each case requires a large propor- 
tion of judgment — a compound of more complex 
composition than any chemical substance ever 
dealt with. 

If any housekeeper finds a method better for 
her purpose than the one specified here, let her 
keep to its use and tell it to others. This work 
will have accomplished its purpose if it interests 
those who understand already the principles of 
cooking and cleaning; gives a few answers to 
those who continually ask "Why?" and "How?" 
and stimulates to study and thought the many 
who have long labored with willing hearts but 
with untrained minds and hands. 

Boston, 1897. 



CONTENTS. 



PAGE 

Preface to First Edition iii 

Preface to Second Edition v 



PART I. 

I. Matter and Its Composition I 

II. Elementary Chemistry 9 

III. Starches, Sugars, Fats, Their Prepara- 

tion as Food 24 

IV. Nitrogenous Constituents 47 

V. Flavors and Condiments. Diet .... 56 

PART II. 

I. Dust 71 

II. Dust Mixtures (Grease and Dust) . . 87 

III. Stains, Spots, Tarnish 100 

IV. Laundry 118 

V. Chemicals for Household Use .... 145 

Books of Reference 153 

Index 155 



THE CHEMISTRY OF COOKING 
AND CLEANING. 



CHAPTER I. 
Matter and Its Composition. 



WE give the name matter to the objects which 
can be recognized by any one of our 
senses. There are many kinds of matter and many 
forms of one kind. Ice melts into water, water 
changes into steam. In our stoves, the hard, black 
coal disappears, leaving a soft, gray ash, that 
weighs much less than the original coal. Some- 
thing has been taken away. 

The leaf is covered by wind-blown soil and soon 
no leaf is there; but the matter of which it was 
composed is still somewhere, for that is never 
lost. Living matter is in constant change from 
one form to another. Our bodies are composed 
of matter, and to their continued existence, as well 
as to their growth, material substances are neces- 
sary. Some changes come quickly, some slowly. 
Years, ages even, are sometimes necessary to 
bring a result that is visible to us. 



Matter. 



2 THE CHEMISTRY OF 

A familiar substance, sugar, for example, may 
be subjected to different changes. Put two table- 
spoonfuls of white sugar into a scant half cup of 
water. The sugar disappears. The clear water 
changes to a syrupy liquid. If the water is allowed 
to evaporate slowly, the sugar is found to remain. 

A teaspoonful of sugar dropped upon the warm 
stove changes in character. There appears a black 
mass, which is readily recognized as charcoal. 

Add a solution of an acid to a solution of an 
alkali, and observe that the acid substance and the 
alkaline substance are no longer in existence as 
such. There is, instead, a neutral saline substance 
dissolved in water. The new substance has the 
properties of neither of the others. The acid and 
the alkali have lost their identity. 

Dissolve a teaspoonful of sugar in a cupful of 
water. Add a very little yeast and put the cup in 
a warm place. Soon bubbles of gas rise and break 
on the surface; while, on distilling the liquid, a 
new acquaintance presents itself in the form 
of alcohol. The first-mentioned change in the 
sugar is a physical change — the character of the 
substance is not permanently altered. The second 
is a chemical change — the substance loses its indi- 
vidual character. The third change in the sugar, 
most important for our present purpose, combines 
chemical and physical changes caused by the ac- 



COOKING AND CLEANING. 3 

tion of life. When the syrup "sours" or ferments, 
we know that living organisms are at work in the 
solution, changing the substance by their own 
processes of growth. To this class, then, we may 
apply the name biological change. Here belong 
the changes in our own bodies which enable them 
to live and grow. Death comes when these "vital" 
changes can no longer proceed in a normal, 
healthy manner. 

Changes in matter, then, are of two kinds. 

I. Physical. Change of form, without change 
of character. This is brought about by outside 
forces: heat, blows, etc. 

II. Chemical. Change of character, with or 
without change of form. This is brought about by 
chemical agencies, by fire and electricity — also 
forces from without. 

Physical and chemical forces, working together, 
allow of biological results, caused by living cells 
producing energy or force by means of their life 
processes. 

Under these heads come the numerous changes 
which every housewife observes and which all 
should understand, so far as such understanding 
is necessary for the true economy of the house. 

We have seen that matter is subject to two kinds X?™* of 

•> JVl atter. 

of change. Experience teaches that matter exists 
in three different forms — solids, liquids and gases. 



4 THE CHEMISTRY OF 

It teaches, also, that by the action of outside forces 
some solids become liquids and some liquids be- 
come gases. The reverse process, also, is known 
— gases change into liquids and liquids into solids. 
The chemist or physicist is able to change matter 
from one form into another in many more in- 
stances than are observed in ordinary experience. 
h r a°n|e C in USmg What force, or forces, cause or can be made to 
tatter. cause these changes? Before an iron kettle or 

stove can be made, the metal from which it is 
formed must be subjected to intense heat, when 
it will become a liquid and can be poured into 
molds of any desired shape. The solid ice melts 
or becomes water at a low temperature; but at a 
higher degree of temperature, the water becomes 
steam or gas. Some solids, as camphor and 
iodine sublime, that is, pass directly into the gas- 
eous form. 

Heat, then, is one force which brings about a 
change of state in material substances. If heat be 
abstracted from a liquid, the latter may become a 
solid, as when water becomes ice. Like changes 
are less readily brought about by pressure, gases 
becoming liquids; liquids becoming solids. Cold 
and pressure, acting together, are able to liquefy 
the air even, and other gases once called per- 
manent. 

The forces exerted from without, then, are press- 
ure, and the addition or subtraction of heat. 



COOKING AND CLEANING. 



Experience teaches that solid and liquid matter 
may be divided into smaller and smaller divisions 
until the particles are no longer visible under a 
powerful microscope. The scientist is led by his 
observations to the belief that matter is made up 
of infinitesimal particles or atoms and that chem- 
ical changes take place among these atoms and 
groups of atoms. They are invisible and inde- 
structible. Each atom occupies space and has 
weight. Two or more atoms united make a mole- 
cule, which also is very far from being visible. It 
may be composed of two or more atoms of the 
same substance or many atoms of different sub- 
stances. 

In the social world there are individuals, fam- 
ilies and communities; so in the material world 
there are atoms, simple molecules and complex 
groups of molecules. The groups or molecules 
are always separated from each other by greater or 
less distances. If the groups are many and the 
distances between them infinitely small, there is 
a "solid crowd." There must be some force to 
widen the distance between the groups and make 
them free to move among themselves. A layer 
of fat is a crowded mass of molecules — a solid. 
Heat drives the molecules apart, increases the dis- 
tance between them, gives them a chance to move 
more freely and produces, thus, the liquid condi- 



Atoms and 
Molecules. 



States of 
Matter. 



6 THE CHEMISTRY OF 

tion. Still further separation, with the breaking 
up of certain groups causes a freedom of move- 
ment in any and all directions, giving a gas or 
gases. If not restrained, these may pass entirely 
beyond our ken though still existent, for "matter 
cannot be created or destroyed at will." 

Different degrees of heat produce varying de- 
grees of liquefaction. The molecules may be 
given only a slight freedom of movement, causing 
a semi-liquid state, as in the melting of solder, of 
gelatine, and of tar. When the molecules are 
driven further apart the mass necessarily occupies 
more space. This is expansion. All matter ex- 
pands or occupies more space under the action of 
heat; but in gases, the proportion of expansion is 
much the greatest, for the molecules have perfect 
freedom of movement. This expansion of gases 
with heat makes possible the process of ventila- 
tion by means of an open fire, and is one factor in 
the rise of dough. 

Into these molecular spaces, molecules of other 
substances may enter. The molecules of solids, 
however, do not readily pass between one another 
in this way. The solids must be changed to 
liquids, that their molecules may have freedom 
of movement. This is commonly brought about 
by solution. 

The degree of solubility of any substance de- 



COOKING AND CLEANING. 7 

pends largely upon the temperature of the sol- 
vent. Common salt dissolves nearly as well in 
cold as in warm water. "Soda" and alum dissolve 
more readily in warm than in cold, while cream 
of tartar requires hot water for its complete solu- 
tion. 

The amount of solid which water will dissolve saturation, 
usually increases with the temperature to a certain 
degree. After this no more will dissolve and the 
solution is "saturated." Gases readily dissolve in 
water, but, usually, in cold solutions only. 

The action of the liquid is increased if the solid 
be first powdered, for a greater area is thus pre- 
sented to the action of the liquid. It is usually 
more rapid when the powder is placed upon the 
surface. Under these conditions each particle, 
while dissolving is surrounded by a thin envelop 
of syrup, which becomes heavier and sweeter. The 
film of syrup is washed away by the solvent liquid, 
so that a clean surface is continually exposed to 
be acted upon. Some particles are so light that 
they will not sink; then the process of solution is 
very slow. Solution is a valuable agent in bring- 
ing about chemical action during many processes 
of cooking and cleaning. 

Water is a nearly universal solvent. It dissolves Solvents, 
larger quantities of more substances than any 
other liquid. Some solids, however, dissolve 



8 COOKING AND CLEANING. 

more readily in other liquids, as camphor in alco- 
hol. Silver, copper and tin are not perceptibly 
dissolved in pure water, while most of their com- 
pounds, as nitrate of silver and sulphate of cop- 
per, are thus soluble. Lead dissolves more readily 
in pure water than in that containing some im- 
purities. Gold may be dissolved in a warm mix- 
ture of two strong acids. Many of these metallic 
solutions which may be formed in cooking uten- 
sils and water pipes are poisonous, and a knowl- 
edge of them becomes a matter of great im- 
portance to all housekeepers. 

A process of daily occurrence in the household 
greatly resembles solution. It consists in the 
taking up of water, which produces an increase of 
bulk or "swelling," but no true solution. Gela- 
tine swells in cold water and may then be dis- 
solved in hot water. Starch "jells" by taking up 
water; so we soak the cereals which consist 
largely of starch, that they may be more quickly 
acted upon by heat. 



CHAPTER II. 
Elementary Chemistry. 

MOST substances with which we deal in ordi- 
nary life are compounds of two or more 
elementary constituents. The grain of wheat, the 
flesh of animals, the dangerous poison, are each 
capable of separation into simpler substances. 
Finally a substance is found which cannot be di- 
vided without losing its identity. The chemical 
element is that substance out of which nothing 
essentially different has ever yet been obtained. 

Pure gold is an element from which nothing Elements. 
can be taken different from itself, but gold coin 
contains a little copper or silver or both. The oxy- 
gen of the air is an element. Air is a mixture of 
two or more elements. Oxygen and hydrogen, 
both gaseous elements, unite in certain propor- 
tions to form the chemical compound, water. 

There are about eighty of these elements known 
to the chemist, while their compounds are infinite. 
For his convenience the chemist abbreviates the 
names of the elements into symbols which he 
uses instead of the names. Usually, the first or 
the first two letters of the Latin name are taken. 



10 



THE CHEMISTRY OF 



These symbols mean much more, however, than 
time saved, as we shall see. 

Most of the elements unite with each other. 
Then in the resulting compounds, one or more 
elements may be exchanged for others, so that a 
multitude of combinations are formed out of few 
elementary substances. The bulk of our food, 
clothing and furniture is made up of only five or six 
of these elements, although about twenty of them 
enter into the compounds used in the household. 
The others are found in nature, in the chemical lab- 
oratory or in the physician's medicine case. A few 
are so rare as to be considered curiosities. 

Every housewife should understand something 
of these chemical substances — their common 
forms, their nature and their reactions, that she 
may not be cheated out of time and money, and, 
more important still, that she may preserve the 
health of those for whom she cares. 

All chemical changes are governed by laws. 
Under like conditions, like results follow. No 
chemical sleight of hand can make one pound of 
washing soda do the work of two pounds, or one 
pound of flour make a third more bread at one 
time than at another. 

It has been assumed that all compounds are 
formed by the union of atoms — those smallest 
homogeneous particles of matter. Each atom has 



COOKING AND CLEANING. 11 

its definite weight, which remains constant. This 
weight is known in chemistry as "atomic weight." 
No single atom can be weighed by itself, but it is 
found that hydrogen is the lightest substance 
known, so the weight of its atom is called one. 
All other substances are compared with this unit, 
i. e., their atoms weigh one, two, three or more 
times the hydrogen atom. 

Reckoned in this way the atom of oxygen £ hei £ i( { al 
weighs sixteen and the carbon atom twelve times 
as much as the atom of hydrogen. The symbol of 
an element, then, represents its constant atomic 
weight; so that, while the word oxygen means 
only the collection of properties to which is given 
the name, the symbol O indicates a definite quan- 
tity which is sixteen times the weight of the H 
atom. 

The number of atoms used is indicated by a small 
figure placed below and at the right of the symbol. 
When no figure appears, one atom is understood. 
In a compound, the number of molecules is desig- 
nated by a large figure at the left of the formula : 
H 2 S0 4 means one molecule containing two atoms 
of hydrogen, one of sulphur, four of oxygen. 
4H 2 S0 4 means four molecules containing eight 
atoms of hydrogen, four of sulphur, sixteen of oxy- 
gen. A little chemical arithmetic is needed to 
compute the weight of these molecules. Molecular 



12 THE CHEMISTRY OF 

weight is the sum of the atomic weights of the 
constituent elements. Our chemical example then 
stands : 

Two atoms of H= 2 

One atom of S^ 32 

Four atoms of O^ 64 



One molecule of H 2 S0 4 =: 98 
Four molecules of H 2 S0 4 =392 



392 what? All weights are referred to the standard 
H ; so the four molecules weigh 392 times as much 
as the hydrogen atom. 

The symbols, then, are the chemist's shorthand 
alphabet, or his sign language. The non-scientific 
reader is apt to look upon the acquisition of this 
sign language as the schoolboy regards the study 
of Chinese — as the work of a lifetime. He would 
be near the truth were he to attempt to remember 
the symbols of all the complicated compounds 
known and constantly increasing; but a study 
of the properties and combinations of the few 
which make the common substances of daily 
use need not frighten the most busy house- 
wife, for they can be comprehended in a few hours 
of thoughtful reading. Then a little practice will 
make them as familiar as the recipe of her favorite 
cake. "To master the symbolical language of 
chemistry, so as to fully understand what it ex- 



COOKING AND CLEANING. 13 

presses, is a great step toward mastering the sci- 
ence." 

Having thus prepared the ground and collected Laws oi 
materials, the foundation may be laid — i. e., the 
laws of chemical combination. It has been said 
that the elements unite with each other and ex- 
change places one with another. In society there 
are persons whose powers of attraction toward 
others vary widely. In conversation upon any 
subject, one person may interest, with ease, one 
individual; another may hold two interested lis- 
teners; while a few, with rare gifts, may hold to- 
gether a group of many. We say the last person 
has a stronger holding power than the other two. 
This may serve to illustrate what is known by ex- 
periment to be a fact among atoms. The chemist 
finds an atom of one element holding to itself one 
atom of a different element; another, holding two; 
while a third may hold three or more. 

Chlorine will hold to itself only one atom of H, 
making HC1, muriatic acid; but O holds two — 
H 2 — water; N holds three — NH 3 — ammonia; 
and C, four — CH 4 — "fire damp.'* 

Under different conditions, some elements show 
different powers of attraction toward the same 
element; so again this chemical society resembles 
social life. Sometimes N will hold to itself one 
atom of O, sometimes two, and sometimes three 
with an atom of H besides. 



14 



THE CHEMISTRY OF 



Exchange 
Value. 



The chemist must understand all these holding 
powers, which he calls the valence of an element; 
but to him the housewife may leave the thorough 
knowledge, while she recognizes that by virtue of 
this valence, compounds are formed with widely 
different qualities; thus, H 2 is pure water, while 
H 2 2 , hydrogen peroxide, is a disinfectant and 
a bleaching agent; S0 2 , sulphur dioxide, used for 
bleaching straw and fabrics, also a germicide, is a 
gas; while S0 3 is a white crystalline solid. 

Valence is a variable quality, but in uniting, or 
exchanging places with each other, the atoms of 
each element have a value which remains constant. 
This value is expressed in terms of a certain unit 
which chemists have chosen as a standard. 

At the outposts of the Hudson's Bay Territory 
all trade is on a system of barter or exchange, and 
therefore a basis of value is necessary. The skin 
of a beaver is agreed upon as the unit from which 
to count all values. A red fox skin is worth two 
beaver skins ; a silver fox skin is worth four beaver 
skins. All the hunter's transactions are based 
upon these values. If he wishes to purchase a 
knife, he must pay four beaver skins; a gun will 
cost him three silver fox or twelve beaver skins. 

The chemist's standard of value is the atomic 
weight of hydrogen. They choose this because it 
is the smallest relative weight known to enter into 



COOKING AND CLEANING. 15 

combination with other elements. Having once 
accepted this arbitrary choice, all values are 
counted from its value. For the convenience of 
the reader, this exchangeable value will be indi- 
cated by Roman numerals over the symbols in the 
formulae given in this book, although this practice 
is not universal. 

The exchange value of other elements is found £o™ s bina " 
by experiment. For our present purpose, these 
elements may be divided into three classes with 
hydrogen for a connecting link. 

Exchange Values. 
Table I. 
Some common elements which unite with H: 

Chlorine CI 1 

Iodine I 1 

Bromine Br 1 1 

Oxygen O 11 > +H 1 

Sulphur S n 

Nitrogen N nI 

Carbon C™ 

H 1 unites with CI 1 , atom for atom, their values 
being the same. O n unites with two of H 1 , its 
value being twice that of H 1 ; while N m equals 
three of H 1 ; and C IV , four. 



16 THE CHEMISTRY OF 

Table II. 

Some common elements which unite with each 
other and with compounds of H. 

Carbon C 1 ^ 

Oxygen O n 

Sodium Na 1 

Potassium K 1 

Calcium Ca 11 

Chlorine CI 1 

Nitrogen N HI 

Sulphur S« 

Phosphorus P v 

C™ unites with 2 n making C IV 2 n , carbon 
dioxide or carbonic acid gas; C IV 2 n unites 
with H 2 I O n forming H 2 I C iy 3 11 , carbonic acid gas 
in solution. Ca 11 unites with O n , forming Ca n O n , 
quicklime; Ca XI O n unites with H^O 11 , forming 
CanH^Oj, 11 , slaked lime. 

Table III. 

Some common elements which may be substi- 
tuted for H in a compound, thereby making a new 
compound : 

Sodium Na 1 

Potassium K 1 

Calcium Ca 11 

Carbon C J V 



COOKING AND CLEANING. 17 

Phosphorus P 111 or PV 

Tin SnH r Sn™ 

Zinc Zn" 

Sulphur S n 

Copper Cu 11 

Lead Pb" 

Gold Auin 

Aluminum Al 11 or A1 IV 

H I C1 I is muriatic or hydrochloric acid. As Na 1 
has the same value as H 1 , it may be substituted for 
it, and we have Na I Cl I , common salt. H 2 I C IV 3 11 
is carbonic acid in solution. Na 2 * may be substi- 
tuted for the H 2 X forming Na^C^Og 11 , the com- 
mercial soda ash. Soda ash added to water and 
allowed to crystallize from it gives the familiar 
"washing crystals." H I N III 3 n is nitric acid. 
One atom of K 1 will replace the H 1 , forming 
K I N III 3 n , or saltpetre. 

Some of the compounds formed by the union Union and 

x Exchange. 

and exchange of these various elements are very 
familiar substances. 

"In the laboratory we never mix our materials at 
random, but always weigh out the exact propor- 
tions . . . for, if the least excess of one or 
the other substance over the proportions indicated 
is taken, that excess will be wasted. It will not 
enter into the chemical change."* It is this exact- 

*"The New Chemistry," p. 151. 



18 



THE CHEMISTRY OF 



ness in dealing with matter which gives to the 
study of chemistry its great value from an educa- 
tional standpoint. In the economy of nature noth- 
ing is lost. Wood and coal burn in our stoves. 
The invisible product of their combustion, C IV 2 n , 
passes into the air, but adds a definite amount to 
the weight of the air. Twelve pounds of coal (free 
from ash) in burning take from the air thirty- 
two pounds of oxygen and give back to the air 
forty-four pounds of carbon dioxide. 

Water is always composed of two atoms of 
hydrogen to one of oxygen, whether the quantity 
formed be one molecule or one million molecules. 
The water molecule, H^O 11 (atomic weights, 
H 2 T =2, O n =i6) weighs 18, then for every 
eighteen parts by weight of water, there will be two 
parts by weight of H 1 and sixteen parts by weight 
of O n . 

C IV 2 n , carbon dioxide, has one atom of carbon 
and two atoms of oxygen in each molecule ; while 
by weight, twelve parts are C IV and thirty-two are 
O n . The exchanges and interchanges among the 
elements according to these two laws of value and 
weight form chemical reactions. The written ex- 
pression of the reaction is called a chemical equa- 
tion. In all chemical equations there is just as 
much weight represented on one side of the sign 
of equality {—) as on the other. 



COOKING AND CLEANING. 



19 



C I v+0 2 II =Civo 2 n 



12 + 32 
Carbon. Oxygen. 

HiCl* + NaiO n Hi = 

Muriat- Caustic 

ic Acid. Soda. 



- 44 
Carbon Dioxide. 

Na^l 1 + HJO" 

Sodium, Water. 

Chloride 
or Com- 
mon Salt. 



36.5+40 =58.5+18 
76.5=76.5 

This shows that the sumi of the weights of the 
two substances taken is equal to the sum of the 
weights of the new substances formed as the result 
of the reaction. These facts lead up to one of the 
fundamental laws of the present science of chemis- 
try — the Law of Definite Proportions: In any 
chemical compound the elements ahvays unite in the 
same definite proportion by weight. 

The atomic weights of elements united in a com- 
pound are then spoken of as the combining 
weights; thus, twelve and thirty-two are the com- 
bining weights of C IV and O n . Out of this first 
law grows a second — the Law of Multiple Propor- 
tions: When elements form more than one com- 
pound, they unite according to some multiple of their 
combining weights. 

As we have noticed, sulphur and oxygen form 
different compounds — S0 2 and SO s — where the 
combining weights are thirty-two to thirty-two 



20 THE CHEMISTRY OF 

for the first and thirty-two to forty-eight for the 
second. 

These two laws are the corner-stones upon 
which all reactions are built. If we wish to obtain 
forty-four pounds of carbon dioxide (carbonic acid 
gas) we may, according to our first law, write out 
the reaction which we know will take place. 

c+o 2 =co 2 

The combining weight of carbon is 12. 

One atom= 12 

The combining weight of oxygen is 16. 

Twt> atoms= 32 

C0 2 = 44 

Then we must take twelve pounds of carbon 
and thirty-two pounds of oxygen to make our de- 
sired forty-four pounds of gas. 

Exchange of When more than two elements enter into corn- 

Groups. 

bination, it is common for two or more to band 
together. In such a case the group has an ex- 
change value of its own, which is not the sum of 
the values of its separate elements, but which is a 
constant value, dependent upon their values in a 
way which it is not necessary to explain here. 
These partnerships will be included in brackets, as 
(SOJ 11 , (C0 3 ) n , (NO.) 1 . These groups do not 
represent actual compounds, which exist alone, 
like lyO 11 , IPCl 1 , C IV 2 n , N^Cl 1 ; but the group 



COOKING AND CLEANING. 



21 



enclosed by the brackets passes from one com- 
pound into another as if it were one element. The 
numeral over the bracketed letters indicates the 
exchange value of the partnership, not the sum 
of the elements. A few illustrations will make 
this clearer. 

Table IV. 

Mineral acids and some of their common com- 
pounds : 



HiQi Hi(N0 3 ) 1 

Muriat- Nitricj 

ic Acid. Acid. 



Compounds : 



NaiQi 

Salt. 



KJCNOs)! 

Saltpetre. 



H,i(SO0 n 

Sulphuric 
Acid. 



Ca«(SO0« 

Plaster of 
Paris. 



H,(CO,)" 

Carbonic 
Acid. 



Ca"(CO.)" 

Marble. 



Reactions among the above substances : 
H 2 i(S04) II +Caii(C0 3 ) II =Ca"(S04) n +H 2 i(C03) n 
H 2 i(SO 4 )n+2(Na I Q I )=Na,i(SO0 II +2(HiCli)i 
H 2 i(S04) II +NaiCl I =NaiHi(S04) II +HiCli 

It will be seen that the groups do not separate, 
but combine and exchange with the single ele- 
ments by the same laws which govern the com- 
binations among simpler substances. 

The last two equations show how, where there 
are two atoms of hydrogen which may be replaced, 



22 THE CHEMISTRY OF 

either one or both can be exchanged for an atom 
of equal replacing value. The two compounds 
thus formed will differ in their properties. This 
will be more fully shown later on in the case of 
cream of tartar. 



COOKING AND CLEANING. 23 



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CHAPTER III. 
Starches, Sugars, Fats, Their Preparation for Food. 

THE material world is divided into living and 
lifeless matter. All living matter requires 
food that it may grow, repair waste, and reproduce 
itself, if the existence of its kind is to be continued. 
This food must be made from the material elements 
we have been studying. Food for the human body 
must, therefore, contain such elements, in com- 
bination, as are found in the body substance, in 
order that new materials may be formed from 
them by the processes of life. 

Wherever there is life, there is chemical change, 
and, as a rule, a certain degree of heat is neces- 
sary, in order that chemical change may occur. 
Vegetation does not begin in the colder climates 
until the air becomes warmed by the heat of the 
spring. When the cold of winter comes upon 
the land, vegetation ceases. If plant life is to be 
sustained during a northern winter, artificial 
warmth must be supplied. This is done by heat 
from a furnace or stove. In chemical terms, car- 
bon and hydrogen from coal, wood, or gas are 
caused to unite with the oxygen of the air to form 
carbon dioxide (carbonic acid gas) and water, and 



COOKING AND -CLEANING. 25 

by this union of two elements with oxygen, heat 
is produced. 

C iv+o 2 n = Civo 2 n 
C I VHJ+04 II =C I vo 2 II +2H 2 iO" 

These two chemical reactions indicate the 
changes which cause the production of artificial 
heat generally used for domestic purposes. All 
living matter, whether plant or animal, is found 
by analysis to contain carbon, oxygen, hydrogen, 
and nitrogen. Other elements are present in small 
and varying quantities, but "the great four" are 
the essentials. The plant is able to take all its 
food elements from air, water and soil, and, in 
its own cells, to manufacture those compounds 
upon which it can feed; while an animal cannot do 
this, but must accept for the most part the manu- 
factured product of the plant. Man, therefore, 
finds his food in both vegetable and animal sub- 
stances. 

Since many animals live in temperatures in 
which plants would die, it is evident that they must 
have some source of heat in themselves. This is 
found in the union of the oxygen of the air 
breathed, with carbonaceous matter eaten as food, 
and the formation of carbonic acid gas (carbon 
dioxide), and water (C0 2 and H 2 0), just as 
in the case of the combustion of the wood in the 
grate. Only, instead of this union taking place in 



26 



THE CHEMISTRY OF 



Vital Tem- 
perature. 



Food Elements 
for Combus- 
tion. 



Oxygen. 



one spot, and so rapidly as to be accompanied by 
light, as in the case of the grate fire, it takes place 
slowly and continuously in each living cell. 
Nevertheless, the chemical reaction seems to be 
identical. 

The heat of the human body must be main- 
tained at 37 C — the temperature necessary for 
the best performance of the normal functions. Any 
continued variation from this degree of heat indi- 
cates disease. Especially important is it that there 
be no considerable lowering of this temperature, 
for a fall of one degree is dangerous. 

The first requirement of animal life is, then, the 
food which supplies the heat necessary for the 
other chemka! changes to take place. The class 
of foods which will be considered here as those 
utilized for the production of animal heat among 
other functions, includes the carbon compounds, 
chiefly composed of carbon, hydrogen and oxygen. 

The slow combustion or oxidation of these car- 
bonaceous bodies cannot take place without an 
abundance of oxygen; hence, the diet of the ani- 
mal must include fresh air — a point too often over- 
looked. The amount of oxygen, by weight, taken 
in daily, is equal to the sum of all the other food 
elements. One-half of these consists of some form 
of starch or sugar — the so-called carbohydrates, 



COOKING AND CLEANING. 



27 



in which the hydrogen and oxygen are found in 
the same proportions as in water. (The fats will 
be considered by themselves.) 

Starches, sugars and gums are among the con- 
stituents of plants, and are sometimes found in 
animals in small quantities. Starch is found in 
greater or less abundance in all plants and is laid 
up in large quantities in the seeds of many species. 
Rice is nearly pure starch, wheat and the other 
cereals contain sixty to seventy per cent of it. 
Some tubers contain it, as potatoes, although in 
less quantity, ten to twenty per cent. It is formed 
by means of the living plant-cell and the sun's 
rays, from the carbon dioxide and water contained 
in the air, and it is the end of the plant life — the 
stored energy of the summer, prepared for the 
early life of the young plant another year. An 
allied substance is called cellulose. This oc- 
curs under numerous forms, in the shells 
and skins of fruits, in their membraneous 
partitions, and in the cell walls. Starch in its com- 
mon forms is insoluble in water. It dissolves par- 
tially in boiling water, forming a transparent jelly 
when cooled. 

Sugars, also, are a direct or indirect product of 
plant life. Common sugar, or cane-sugar, occurs 
in the juices of a few grasses, as the sugar-cane; 
of some trees; and of some roots. Milk-sugar is 



Starches. 



Sugars. 



28 THE CHEMISTRY OF 

found in the milk of mammalia, while grape-sugar 
is a product of the ripening processes in fruit. 

Digestion is primarily synonymous with solu- 
tion. All solid food materials must become prac- 
tically soluble before they can pass through the 
walls of the digestive system. As a rule, non-crys- 
talline bodies are not diffusible, so that starch and 
like materials must be transformed into soluble, 
crystalline substances, before absorption can take 
place. Cane-sugar, too, has to undergo a chemical 
change before it can be absorbed; but grape and 
milk sugars are taken directly into the circula- 
tion. To this fact is due a part of the great nu- 
tritive value of dried fruits as raisins, dates and 
figs, and the value of milk-sugar over cane-sugar, 
for children or invalids. Chemically pure milk- 
sugar can now be obtained at wholesale for about 
35 cents per pound. This may be used in certain 
diseases when cane-sugar is harmful. The chemi- 
cal transformations of starch and sugar have been 
very carefully and scientifically studied with refer- 
ence to brewing and wine-making. Several of the 
operations concerned necessitate great precision in 
respect to temperature and length of time, and 
these operations bear a close analogy to the 
process of bread-making by means of yeast. The 
general principles on which the conversion of 
starch into sugar, and sugar into alcohol, are con- 



COOKING AND CLEANING. 



29 



ducted will therefore be stated as preliminary to a 
discussion of starch and sugar as food. 

There are two distinct means known to the 
chemist, by which this change can be produced. 
One is by the use of acid and heat, which changes 
the starch into sugar, but can go no farther. The 
other is by the use of a class of substances called 
ferments, some of which have the power of chang- 
ing the starch into sugar, and others of changing 
the sugar into alcohol and carbon dioxide. These 
ferments are in great variety and the seeds of 
some of them are always present in the air. Among 
the chemical substances called ferments, one is 
formed in sprouting grain which is called diastase 
or starch converter, which first, under the in- 
fluence of warmth, changes the starch into a sugar, 
as is seen in the preparation of malt for brewing. 
The starch (C 6 H 10 O 5 ), first takes up water (H 2 0), 
and, under the influence of the ferment, is changed 
into maltose. Cane-sugar is readily converted 
into two sugars, dextrose and levulose, belonging 
to the glucoses. 



Starch Con- 
version. 



Ci 2 IV H 22 i0 1 i II +H 2 iO II +ferment=2C 6 IV H 12 i0 6 11 

Cane-Sugar. Water. Dextrose and Levulose. 

Glucose and maltose are converted by yeast into Sugar m 

111 Conversion. 

alcohol and carbon dioxide. In beer, the alcohol 
is the product desired, but in bread-making the 



30 THE CHEMISTRY OF 

chief object of the fermentation is to produce car- 
bon dioxide to puff up the bread, while the al- 
cohol escapes in the baking. 

{2C 2 i vh 6 i O" 
Alcohol. 
2Civo 2 " 
Carbon Dioxide. 

The alcohol, if burned, would give carbon dioxide 
and water. 

2C 2 IV H 6 I 0"+i20 11 = 4Civo 2 n -{-6H 2 I 11 

Alcohol. Oxygen. Carbon Dioxide. Water. 

It will be seen, from the previous equations, 
that nothing has been lost during the process. 
The six atoms of carbon in the original starch 
reappear in the carbon dioxide at the end, 
2C0 2 +4C0 2 . Two atoms of hydrogen from the 
water, and thirteen atoms of oxygen from the 
water and the air have been added. Reckoning 
the atomic weights of the starch used, the carbon 
dioxide and the water formed, we find that, in 
round numbers, sixteen pounds of starch will yield 
twenty-six pounds of gas and ten pounds of water, 
or more than double the weight of the starch. 
These products of decomposition are given back 
to the air in the same form in which those sub- 
stances existed from which the starch was orig- 
inally formed. 

The same cycle of chemical changes goes on in 
the human body when starchy substances are 



COOKING AND CLEANING. 31 

taken as food. Such food, moistened and warmed 
in the mouth, becomes mixed with air through 
mastication, by reason of the property of the sa- 
liva to form froth, and also becomes impregnated 
with ptyalin, a substance which can change starch 
into sugar as can the diastase of the malt. The 
mass then passes into the stomach, and the 
change, once begun, goes on. As soon as the 
sugar is formed, it is absorbed into the circu- 
latory system and, by the life processes, is oxi- 
dized, i. e., united with more oxygen and changed 
finally into carbon dioxide and water. 

No starch is utilized in the human system as 
starch. It must undergo transformation before it 
can be absorbed. Therefore starchy foods must 
not be given to children before the secretion of 
the starch converting ferments has begun, nor to 
any one in any disease where the normal action of 
the glands secreting these ferments is interrupted. 
Whatever starch passes out of the stomach 
unchanged, meets a very active converter in 
the intestinal juice. If grains of starch escape 
these two agents, they leave the system in the 
same form as that in which they entered it. 

Early man, probably, lived much like the beasts, 
taking his food in a raw state. Civilized man re- 
quires much of the raw material to be changed, by 
the action of heat, into substances more palatable 
and already partly digested. 



32 THE CHEMISTRY OF 

The chemistry of cooking the raw materials is 
very simple. It is in the mixing of incongruous 
materials in one dish or one meal that complica- 
tion arises. 

Since fully one-half of our food is made up of 
starches and sugars, it is pertinent to examine, 
beside their chemical composition, the changes 
which they may undergo in the processes of cook- 
ing that can render them more valuable as food, 
or which, on the other hand, may in large meas- 
ure destroy their food value. 

The cooking of starch, as rice, farina, etc., re- 
quires little explanation. The starch grains are 
prepared by the plant to keep during a season of 
cold or drought and are very close and compact; 
they need to be swollen and distended by moisture 
in order that the chemical change may take place 
readily, as it is a law, that the finer the particles, 
the sooner a given change takes place, as has 
been explained in a previous chapter. Starch 
grains may increase to twenty-five times their bulk 
during the process of hydration. 

The cooking of the potato and other starch-con- 
taining vegetables, is likewise a mechanical proc- 
ess very necessary as a preparation for the chem- 
ical action of digestion; for raw starch has been 
shown to require a far longer time and more di- 
gestive power than cooked starch. Change takes 



COOKING AND CLEANING. 33 

place slowly, even with thorough mastication, un- 
less the starch is heated and swollen, and, in case 
the intestinal secretion is disturbed, the starch 
may not become converted at all. 

The most important of all the articles of diet Bread, 
which can be classed under the head of starchy 
foods is bread. Wheat bread is not all starch, but 
it contains a larger percentage of starch than of 
anything else, and it must be discussed under this 
topic. Bread of some kind has been used by man- 
kind from the first dawn of civilization. During 
the earlier stages, it consisted chiefly of powdered 
meal and water, baked in the sun, or on hot 
stones. This kind of bread had the same charac- 
teristics as the modern sea-biscuit, crackers and 
hoe-cake, as far as digestibility was concerned. It 
had great density, it was difficult to masticate, 
and the starch in it presented but little more sur- 
face to the digestive fluids than that in the hard 
compact grain, the seed of the plant. 

Experience must have taught the semi-civilized 
man that a light porous loaf was more digestible 
than a dense one. Probably some dough was ac- 
cidentally left over, yeast plants settled upon it 
from the air, fermentation set in, and the possibil- 
ity of porous bread was thus suggested. 

The small loaf, light, spongy, with a crispness 
and sweet, pleasant taste, is not only aesthetically, 



34 THE CHEMISTRY OF 

but chemically, considered the best form in which 
starch can be presented to the digestive organs. 
The porous condition is desired in order that as 
large a surface as possible shall be presented to 
the action of the chemical converter, the ptyalin 
of the saliva, and, later, to other digestive fer- 
ments. There is also a better aeration in the proc- 
ess of mastication. 

The ideal bread for daily use should fulfill cer- 
tain dietetic conditions: 

i. It should retain as much as possible of the 
nutritive principles of the grain from which it is 
made. 

2. It should be prepared in such a manner as to 
secure the complete assimilation of these nutri- 
tive principles. 

3. It should be light and porous, so as to allow 
the digestive juices to penetrate it quickly and 
thoroughly. 

4. It should be especially palatable, so that one 
may be induced to eat enough for nourishment. 

5. It should be nearly or quite free from coarse 
bran, which causes too rapid muscular action to 
allow of complete digestion. This effect is also 
produced when the bread is sour. 

Ordinary Graham bread, brown bread and the 
black bread of Germany fulfill conditions 1 and 4, 
but fail in the other three. Bakers' bread of fine 



COOKING AND CLEANING. 35 

white flour fulfills 2, 3 and 5, but fails in the other 
two. Home-made bread often fulfills conditions 
4 and 5, but fails in the other three. 

Very early in the history of the human race tf&S* ° r 
leavened bread seems to have been used. This was 
made by allowing flour and water to stand in a 
warm place until fermentation had well set in. A 
portion of this dough was used to start the process 
anew in fresh portions of flour and water. This 
kind of bread had to be made with great care, for 
germs different from yeast might get in, forming 
lactic acid — the acid of sour milk — and other sub- 
stances unpleasant to the taste and harmful to the 
digestion. 

Butyric acid occurs in rancid butter and in many 
putrified organic substances. A sponge made from 
perfectly pure yeast and kept pure may stand for a 
long time after it is ready for the oven and still 
show no sign of sourness. 

On account of the disagreeable taste of leaven 
and because of the possibility that the dough might 
reach the stage of putrid fermentation, chemists 
and physicians sought for some other means of 
rendering the bread light and porous. The search \ 
began almost as soon as chemistry was worthy the 
name of a science, and one of the early patents 
bears the date 1837. Much time and thought have 
been devoted to the perfecting of unfer- 



Chemical Re- 
actions in 
Bread-Mak- 
ing. 



36 THE CHEMISTRY OF 

merited bread; but since the process of beer- 
making has been universally introduced, yeast has 
been readily obtained, and is an effectual means of 
giving to the bread a porous character and a pleas- 
ant taste. Since the chemistry of the yeast fer- 
mentation has been better understood, a change of 
opinion has come about, and nearly all scientific 
and medical men now recommend fermented bread. 

The bacteriology of bread and bread-making is 
yet somewhat obscure. The ordinary yeasts are so 
mingled with bacteria that the part which each 
plays is not yet understood. Only experiments 
long continued will solve these problems. 

The chemical reactions concerned in bread- 
raising are similar to those in beer-making. To 
the flour and warmed water is added yeast, a mi- 
croscopic plant, capable of causing the alcoholic 
fermentation. The yeast begins to act at once, but 
slowly; more rapidly if sugar has been added and 
the dough is a semi-fluid. Without the addition 
of sugar no change is evident to the eye for some 
hours, as the fermentation of sugar from starch, by 
the diastase, gives rise to no gaseous products. As 
soon as the sugar is decomposed by the yeast plant 
into alcohol and carbonic acid gas (carbon diox- 
ide), the latter product makes itself known by the 
bubbles which appear and the consequent swelling 
of the whole mass. 



COOKING AND CLEANING. 37 

It is the carbon dioxide which causes the sponge- 
like condition of the loaf by reason of the peculiar 
tenacity of the gluten, one of the constituents of 
wheat. It is a well-known fact that no other kind 
of grain will make so light a bread as wheat. It is 
the right proportion of gluten (a nitrogenous sub- 
stance to be considered later) which enables the 
light loaf to be made of wheat flour. 

The production of carbon dioxide is the end of * 
the chemical process. The rest is purely mechanical. ' 
The kneading is for the purpose of rendering the 
dough elastic by the spreading out of the already 
fermented mass and its thorough incorporation 
with the fresh flour. Another reason for kneading 
is, that the bubbles of gas may be broken up into 
as small portions as possible, in order that there 
may be no large holes, only very fine ones, 
evenly distributed through the loaf, when it is 
baked. 

The temperature at which the dough should be Temperature 

, 1 • • , • • ofBread- 

maintained during the chemical process is an 1m- Making, 
portant point. If the characteristics of ''home- 
made" bread are desired, it is found to be better to 
use a small amount of yeast and to keep the dough 
at a temperature from 55 degrees to 60 degrees for 
twelve to fifteen hours, than to use a larger quantity 
of yeast and to cause its rapid growth. The changes 
which produce the desired effect are not fully under- 



38 THE CHEMISTRY OF 

stood. Above 90 degrees the production of acetic 
acid — the acid of vinegar — is liable to occur: for 
this temperature, while unfavorable for the yeast 
plant, is favorable for the growth of the particular 
bacterium which produces acetic acid. 

C 2 IV H 6 iO I i+0 2 II =C 2 I VH 4 I 2 II +H 2 iOn 

Alcohol. Acetic Water. 

Acid. 

After the dough is stiffened by a little fresh flour 
and is nearly ready for the oven, the temperature 
may be raised, for a few minutes, to 100 degrees 
or 165 degrees F. The rapid change in the yeast is 
soon stopped by the heat of the oven. 

The baking of the loaf has for its object to kill 
the ferment, to heat the starch sufficiently to render 
it easily soluble, to expand the carbon dioxide and 
drive off the alcohol, to stiffen the gluten, and to 
form a crust which shall have a pleasant flavor. 
The oven must be hot enough to raise the tempera- 
ture of the inside of the loaf to 212 degrees F., or 
the bacteria will not all be killed. A pound 
loaf, four inches by four by nine, may 
be baked three-quarters of an hour in an 
oven where the initial temperature is 400 
degrees F., or for an hour and a half, where 
the temperature during the time does not rise above 
350 degrees F. Quick baking gives a white loaf, 
because the starch has undergone but little change. 



COOKING AND CLEANING. 39 

The long, slow baking gives a yellow tint, with the 
desirable nutty flavor, and crisp crust. Different 
flavors in bread are supposed to be caused by the 
different varieties of yeast used or by bacteria, 
which are present in all doughs, as ordinarily 
prepared. 

The brown coloration of the crust, which gives 
a peculiar flavor to the loaf, is caused by the forma- 
tion of substances analogous to dextrine and cara- 
mel, due to the high heat to which the starch is 
subjected. 

One hundred pounds of flour are said to make 
from 126 to 150 pounds of bread. This increase of 
weight is due to the incorporation of water, pos- 
sibly by a chemical union, as the water does not 
dry out of the loaf, as it does out of a sponge. The 
bread seems moist when first taken from the oven, 
and dry after standing some hours, but the weight 
will be found nearly the same. It is this probable 
chemical change which makes the difference, to 
delicate stomachs, between fresh bread and stale. A 
thick loaf is best when eaten after it is twenty-four 
hours old, although it is said to be "done" when 
ten hours have passed. Thin biscuits do not show 
the same ill effects when eaten hot. The bread 
must be well baked in any case, in order that the 
process of fermentation may be stopped. If this be 
stopped and the mastication be thorough, so that 



40 



THE CHEMISTRY OF 



Expansion of 
Water into 
Steam. 



Methods of 
Obtaining 
Carbon dioxide. 



the bread is in finely divided portions instead of in 
a mass or ball, the digestibility of fresh and stale 
bread is about the same. 

The expansion of water or ice into seventeen 
hundred times its volume of steam is sometimes 
taken advantage of in making snow-bread, water- 
gems, etc. It plays a part in the lightening of 
pastry and crackers. Air, at 70 degrees, doubles 
its volume at a temperature of 560 F., so that if air 
is entangled in a mass of dough, it gives a certain 
lightness when the whole is baked. This is the 
cause of the sponginess of cakes made with eggs. 
The viscous albumen catches the air and holds it, 
even when it is expanded, unless the oven is too 
hot, when the sudden expansion is liable to burst 
the bubbles and the cake falls. 

As has been said, the production of the porous 
condition, by means of carbon dioxide, generated 
in some other way than by the decomposition of 
starch, was the study of practical chemists for some 
years. 

A simple method for obtaining the carbon diox- 
ide is by heating bicarbonate of sodium. 

2NaiHiCivo 3 n +heat = Na 2 iC™O a n +H a iO"+CivOa« 

The bicarbonate splits up into sodium carbonate, 
water, and carbon dioxide. The bread is light but 
yellow. Some of the carbonate remains in the 



COOKING AND CLEANING. 41 

bread, and as it neutralizes the acid of the gastric 
juice, digestion may be retarded. It also acts upon 
the gluten producing an unpleasant odor. 

Among the first methods proposed was one un- 
doubtedly the best theoretically, but very difficult 
to put in practice, viz., the liberation of carbon 
dioxide from bicarbonate of sodium by means of 
muriatic acid. 

NaiHiCiV0 3 II +HiCl I =NaiQ I +H 2 i0i I +C I V0 2 " 

" Soda." Hydrochloric Common Water. Carbon dioxide. 

Acid. Salt. 

This liberation of gas is instantaneous on the con- 
tact of the acid with the "soda," and only a skilled 
hand can mix the bread and place it in the oven 
without the loss of much of the gas. Tartaric acid, 
the acid phosphates, sour milk (lactic acid), vinegar 
(acetic acid), alum — all of which have been used — 
are open to the same objection. Cream of tartar 
is the only acid substance commonly used which 
does not liberate the gas by simple contact when 
cold. It unites with "soda" only when heated, be- 
cause it is so slightly soluble in cold water. For the 
even distribution of the gas by thorough mixing, 
cream of tartar would seem to be the best; but as, 
beside gas, there are other products which remain 
behind in the bread in the case of all the so-called 
baking powders, the healthfulness of these residues 
must be considered. 



42 THE CHEMISTRY OF 

Common salt is the safest, and perhaps the resi- 
dues from acid phosphate are next in order. 

The tartrate, lactate and acetate of sodium are 
not known to be especially hurtful. As the im- 
portant constituent of Seidlitz powders is Rochelle 
salt, the same compound as that resulting from the 
use of cream of tartar and "soda," it is not likely to 
be very deleterious, taken in the small quantities 
in which even habitual "soda biscuit" eaters take it. 

The various products formed by the chemical de- 
composition of alum and "soda" are possibly the 
most injurious, as the sulphates are supposed to be 
the least readily absorbed salts. Taking into con- 
sideration the advantage given by the insolubility 
of cream of tartar in cold water, and the compara- 
tively little danger from its derivative — Rochelle 
salt — it would seem to be, on the whole, the best 
substance to add to the soda in order to liberate 
the gas; but the proportions should be chemically 
exact, in order that there be no excess of alkali to 
hinder digestion. Hence, baking powders pre- 
pared by weight and carefully mixed, are a great 
improvement over cream of tartar and "soda" 
measured separately. As commonly used, the 
proportion of soda should be a little less than 
half. The table on page 23 gives the chemical re- 
actions of the more common baking powders. 



COOKING AND CLEANING. 



43 



Fats. 

Another group of substances which, by their 
slow combustion or oxidation in the animal body, 
yield carbon dioxide and water and furnish heat 
to the system, is called fats. These comprise the 
animal fats — suet, lard, butter, etc. — and the vege- 
table oils — olive oil, cottonseed oil, the oily matter 
in corn, oats, etc. 

Fats, ordinarily so called, are simply solidified 
oils, and oils are liquid fats. The difference be- 
tween them is one of temperature only; for, within 
the body, all are fluid. In this fluid condition, they 
are held in little cells which make up the fatty 
tissues. 

These fatty materials all have a similar composi- 
tion, containing, when pure, only carbon, hydro- 
gen, and oxygen. They differ from starch and 
sugar in the proportion of oxygen to the carbon 
and hydrogen, there being very little oxygen rela- 
tively in the fatty group, hence more must be 
taken from the air for their combustion. 



Composition 
of Fats. 



Cis^HsJOaH 

Stearic Acid in Suet. 



Cc^H^Os 11 

Starch. 



One pound of starch requires one and two-tenths 
pounds of oxygen, while one pound of suet re- 
quires about three pounds of oxygen for perfect 
combustion. This combination of oxygen with the 



Combustion 
of Fats. 



44 THE CHEMISTRY OF 

excess of hydrogen, as well as with the excess of 
carbon results in a greater quantity of heat from 
fat, pound for pound, than can be obtained from 
starch or sugar. Recent experiments have proved 
that the fats yield more than twice as much heat as 
the carbohydrates; hence people in Arctic regions 
require large amounts of fat, and, everywhere, the 
diet of winter should contain more fat than that of 
summer. 

While the chemical expression of these changes 
is that of heat produced, it must be remembered 
that energy or work done by the body is included, 
and that both fats and carbohydrates are the source 
of this energy, and that they must be increased in 
proportion as the mechanical work of the body in- 
creases. If a quantity is taken at any one time 
greater than the body needs for its work, the sur- 
plus will be deposited as a bank account, to be 
drawn from in case of any lack in the future supply 
of either. 

This double source of energy has a large 
economic value, for it has been noticed that in com- 
munities where fats are dear, the required amount 
of heat-giving and energy-producing food is made 
up by a larger proportion of the cheaper carbo- 
hydrates. This prevents too large a draft on the 
bank account. It has also been noticed that wage- 
earners do use a large proportion of fat, whenever 
it is within their means. 



COOKING AND CLEANING. 



45 



Numerous investigations into the condition of 
the insane, as well as of the criminal classes, show 
the results of too little nutrition and the absence of 
sufficient fat. The diet of school children should 
be carefully regulated with the fat supply in view. 
Girls, especially, show, at times, a dislike to fat and 
an overfondness for sugar. They should have the 
proper proportion of fat furnished by butter, cream, 
or, if need be, in disguised form. The cook must 
remember that the butter absorbed from her cake 
tin or the olive oil on her salad is food, as well as 
the flour and eggs. 

The essential oils, although very important, as 
will be shown in the chapter on flavors, occur in 
such small quantities that they need not be con- 
sidered here, except by way of caution. These oils 
are all volatile, and, therefore, will be dissipated by 
a high temperature. 

The digestion of fats is mainly a process of emul- 
sion. With the intestinal fluids, the bile, especially, 
the fats form an emulsion in which the globules 
are finely divided, and rendered capable of passing 
through the membranes into the circulatory sys- 
tem. The change, if any, is not one destructive 
of the properties of the fatty matters. 

If we define cooking as the application of heat, 
then whatever we do to fats in the line of cooking 
them is liable to hinder rather than help their diges- 



Necessity of 
Fat in the 
Diet. 



The Digestion 
of Fat. 



46 COOKING AND CLEANING. 

tibility. The flavor which cooking gives to food 
materials containing fat is, in general, due not to 
any flavor of the fat but to substances produced 
in the surrounding tissues. 

Fats may be heated to a temperature far above 
that of boiling water without showing any change ; 
but there comes a point, different for each fat, 
where reactions take place, the products of which 
irritate the mucous membranes and, therefore, in- 
terfere with digestion. It is the volatile products of 
such decomposition which cause the familiar action 
upon the eyes and throat during the process of 
frying, and, also, the tell-tale odors throughout the 
house. The indigestibility of fatty foods, or foods 
cooked in fat, is due to these harmful substances 
produced by the too high temperature. It must 
not be inferred from what has been said that the 
oxidation of starch and fat is the only source of 
heat in the animal body. A certain quantity is un- 
doubtedly derived from the chemical changes of 
the other portions of food, but the chemistry of 
these changes is not yet fully understood. 



CHAPTER IV. 



Nitrogenous Constituents. 

THE animal body is a living machine, capable 
of doing work — raising weights, pulling loads, 
and the like. The work of this kind which it does 
can be measured by the same standard as the work 
of any machine, i. e., by the mechanical unit of 
energy — the foot-ton. 

The power to do mechanical work comes from 
the consumption of fuel, — the burning of wood, 
coal or gas; and this potential energy of fuel is often 
expressed in units of heat or calories, a calorie being 
nearly the amount of heat required to raise two 
quarts of water one degree Fahrenheit. The ani- 
mal body also requires its fuel, namely food, in 
order to do other work — its thinking, its talking or 
even its worrying. 

The animal body is more than a machine. It 
requires fuel to enable it not only to ivork but also 
to live, even without working. About one-third of 
the food eaten goes to maintain its life, for while 
the inanimate machine is sent periodically to the 
repair-shop, the living machine must do its own 



Animal Body 
a Machine. 



Calories. 



Need of Body 
Fuel. 



48 THE CHEMISTRY OF 

repairing, day by day, and minute by minute. 
Hence it is that the estimations of the fuel and re- 
pair material needed to keep the living animal body 
in good working and thinking condition are, in the 
present state of our knowledge, somewhat empir- 
ical; but it is believed that, within certain wide 
limits, useful calculations can be made by any one 
willing to give a little time and thought to the sub- 
ject. Our knowledge may be rapidly increased if 
such study is made in many localities and under 
varying circumstances. 

The adult animal lives, repairs waste, and does 
work; while the young animal does all these and 
more — it grows. For growth and work something 
else is needed beside starch and fat. The muscles 
are the instruments of motion, and they must grow 
and be nourished, in order that they may have 
power. The nourishment is carried to them by the 
blood in which, as well as in muscular tissue, there 
is found an element which we have not heretofore 
considered, namely, nitrogen. It has been proved 
that the wear and tear of the muscles and brain 
causes the liberation of nitrogenous compounds, 
which pass out of the system as such, and this loss 
must be supplied by the use of some kind of food 
which contains nitrogen. Starch and fat do not 
contain this element; therefore they cannot furnish 
it to the blood. 



COOKING AND CLEANING. 49 

Nitrogenous food-stuffs comprise at least two FoodTtX 5 
large groups, the Albumins or Proteids and the 
Albuminoids. 

Albumins. 

The Albumins in some form are never absent 
from animal and vegetable organisms. They are 
more abundant in animal flesh and in the blood. 
The typical food of this class is the white of tgg, 
which is nearly pure albumin. Other common arti- 
cles of diet belonging to this group are the casein 
of milk, the musculin of animal flesh, the gluten of 
wheat, and the legumin of peas and beans. 

Egg albumin is soluble in cold water, but coagu- 
lates at about 160 degrees F. At this point it is 
tender, jelly-like, and easily digested, w r hile at a 
higher temperature it becomes tough, hard and sol- 
uble with difficulty. 

The albumin of flesh is contained largely in the 
blood; therefore the juices of meat extracted in cold 
water form an albuminous solution. If this be 
heated to the right temperature the albumin is 
coagulated and forms the "scum" which many a 
cook skims off and throws away. In doing this 
she wastes a large portion of the nutriment. She 
should retain this nutrition in the meat by the quick 
coagulation of the albumin of the exterior, which 
will prevent further loss, or use the nutritive solu- 



50 



THE CHEMISTRY OF 



tion in the form of soups or stews. "Clear soups" 
have lost much of their nutritive value and, there- 
fore, belong among the luxuries. 

Albuminoids. 

The animal skeleton — horns, bones, cartilage, 
connective tissue, etc., contain nitrogenous com- 
pounds which are converted by boiling into sub- 
stances that form with water a jelly-like mass. 
These are known as the gelatins. 

The chief constituent of the connective tissues is 
collagen. This is insoluble in cold water, but in hot 
water becomes soluble and yields gelatine. Colla- 
gen swells when heated and when treated with 
dilute acids. Steak increases in bulk when placed 
over the coals, and tough meat is rendered tender 
by soaking in vinegar. Freshly killed meat is tough, 
for the collagen is dry and hard. In time it becomes 
softened by the acid secretions brought about 
through bacterial action, and the meat becomes 
tender and easily masticated. Tannic acid has the 
opposite effect upon collagen, hardening and 
shrinking it. This effect is taken advantage of in 
tanning, and is the disadvantage of boiled tea as 
a beverage. 

Cooking should render nitrogenous food more 
soluble because here, as in every case, digestibility 
means solubility. Therefore, when the white of 



COOKING AND CLEANING. 51 

egg (albumin), the curd of milk (casein), or the glu- 
ten of wheat are hardened by heat, a much longer 
time is required to effect solution. 

As previously stated, egg albumin is tender and Eggs. 
jelly-like when heated from 160 degrees to 180 de- 
grees. This fact should never be forgotten in the 
cooking of eggs. Raw eggs are easily digested 
and are rich in nutrition; when heated just enough 
to coagulate the albumin or "the white," their di- 
gestibility is not materially lessened; but when 
boiled the albumin is rendered more difficultly 
soluble. 

To secure the greatest digestibility in combina- 
tion with palatibility, they may be put into boiling 
water, placed where the temperature can be kept 
below 1 80 degrees, and left from ten to fifteen min- 
utes, or even longer, as the albumin will not harden 
and the yolk will become mealy. 

To fry eggs the fat must reach a temperature — 
300 degrees or over — far above that at which the 
albumin of the egg becomes tough, hard, and well- 
nigh insoluble. 

The oyster, though not rich in nutrition, is read- Oysters, 
ily digested when raw or slightly warmed. When 
fried in a batter, it is so protected by the water in 
the dough that the heat does not rise high enough 
to render insoluble the albuminous morsel within. 
Frying in crumbs (in which there is always 30 to 40 



52 THE CHEMISTRY OF 

per cent water, even though the bread be dry) is 
another though less efficient method of protection 
for the albumin. Corn meal, often used as a coat- 
ing, contains 10 to 12 per cent of water. 

Experiments on the digestibility of gluten have 
proved that a high temperature largely decreases 
its solubility. Subjected to artificial digestion for 
the same length of time, nearly two and one half 
times as much nitrogen was dissolved from the raw 
gluten as from that which had been baked.* 

When gluten is combined with starch, as in the 
cereals, the difficulties of correct cooking are many, 
for the heat which increases the digestibility of the 
starch decreases that of the gluten. 

The same principle applies to casein — the albu- 
minous constituent of milk. There seems to be no 
doubt that boiling decreases its solubility, and, con- 
sequently, its digestibility for persons of delicate 
digestive power. 

The cooking of beans and all leguminous vege- 
tables should soften the cellulose and break up 
the compact grains of starch. Vegetables should 
never be cooked in hard water, for the legumin of 
the vegetable forms an insoluble compound with 
the lime or magnesia of the water. 

In the case of flesh the cooking should soften 

*The Effect of Heat upon the Digestibility of Gluten, by Ellen H. Richards. 
A. M., S. B., and Elizabeth Mason, A. B. Technology Quarterly, Vol. vii., 63. 



COOKING AND CLEANING. 53 

and loosen the connective tissue, so that the little 
bundles of fibre which contain the nutriment may 
fall apart easily when brought in contact with the 
teeth. Any process which toughens and hardens 
the meat should be avoided. 

Whenever it is desired to retain the juices within 
the meat or fish, it should be placed in boiling water 
that the albumin of the surface may be hardened 
and so prevent the escape of the albumin of the 
interior. The temperature should then be low- 
ered and kept between 160 and 180 degrees 
during the time needed for the complete break- 
ing down of the connective tissues. When 
the nutriment is to be used in broths, stews 
or soups, the meat should be placed in cold 
water, heated very slowly and the temperature 
not allowed to rise above 180 degrees until the 
extraction is complete. To dissolve the softened 
collagen, a temperature of 212 degrees is necessary 
for a short time. 

The object of all cooking is to make the food- 
stuffs more palatable or more digestible or both 
combined. 

In general, the starchy foods are rendered more 
digestible by cooking; the albuminous and fatty 
foods less digestible. 

The appetite of civilized man craves and custom 
encourages the putting together of raw materials 



54 THE CHEMISTRY OF 

of such diverse chemical composition that the 
processes of cooking are also made complex. 

Bread — the staff of life — requires a high degree 
of heat to kill the plant-life, and long baking to 
prepare the starch for solution; while, by the same 
process, the gluten is made less soluble. 

Fats, alone, are easily digested, but in the ordi- 
nary method of frying, they not only become de- 
composed themselves, and, therefore, injurious; 
but they also prevent the necessary action of heat, 
or of the digestive ferments upon the starchy ma- 
terials with which the fats are mixed. 

Pastry owes its harmful character to this inter- 
ference of fat with the proper solution of the starch. 
Good pastry requires the intimate mixture of flour 
with solid fat. The starch granules of the flour 
must absorb water, swell, and burst before they can 
be dissolved. The fat does not furnish enough 
water to accomplish this, and it so coats the starch 
granules as to prevent the sufficient absorption of 
water in mixing, or from the saliva during mas- 
tication. This coating of fat is not removed till 
late in the process of digestion. The same effect is 
produced by the combining of flour and fat in 
made gravies. 

The effect of cooking upon the solubility of the 
three important food-principals may be broadly 
stated thus : — 



COOKING AND CLEANING. 55 

Starchy foods are made more soluble by long 
cooking at moderate temperatures or by heat 
high enough to dextrinize a portion of the starch, 
as in the brown crust of bread. 

Nitrogenous foods. The animal and vegetable 
albumins are made less soluble by heat; the animal 
albuminoids more soluble. 

Fats are readily absorbed in their natural condi- 
tion, but are decomposed at very high temperatures 
and their products become irritants. 



CHAPTER V. 

The Art of Cooking. 
Flavors and Condiments. 

THE science as well as the art of cooking lies in 
the production of a subtle something which 
gives zest to the food and which, though infinites- 
imal in quantity, is of priceless value. It is the 
savory potage, the mint, anise and cummin, the 
tasteful morsel, the appetizing odor, which is, 
rightly, the pride of the cook's heart. 

The most general term for this class of stimu- 
lating substances is, perhaps, flavor — the gout of 
the French, the Genuss-Mittel (enjoyment-giver) of 
the Germans. 

The development of this quality in food — taste, 
savor, relish, flavor or what not, which makes "the 
mouth water," depends, in every case, upon chem- 
ical changes more subtle than any others known 
to us. The change in the coffee berry by roasting 
is a familiar illustration. The heat of the fire causes 
the breaking up of a substance existing in the berry 
and the production of several new ones. If the 
heat is not sufficient, the right odor will not be 



COOKING AND CLEANING. 5*7 

given ; if it is too great, the aroma will be dissipated 
into the air or the compound will be destroyed. 

This is an excellent illustration of the narrow Nature of 
margin along which success lies. It is also chem- 
ically typical of the largest number of flavors, 
which seem to be of the nature of oils, set free by 
the breaking up of the complex substances of which 
they form a part. Nature has prepared these essen- 
tial oils by the heat of the sun. They give the taste 
to green vegetables ; while in fruits they are present 
with certain acids, and both together cause the 
pleasure-giving and therapeutic effects for which 
fruit is noted. 

It is probable that the flavors of roasted corn, 
well-cooked oatmeal, toasted bread, also belong to 
this class. Broiled steak and roasted turkey are 
also illustrations, and with coffee show how easily 
the mark is overstepped — a few seconds too long, 
a very few degrees too hot, and the delicate morsel 
becomes an acrid, irritating mass. 

From this standpoint, cooking is an art as exact 
as the pharmacist's, and the person exercising it 
should receive as careful preparation; for these 
flavors, which are so highly prized, are many of 
them the drugs and poisons of the apothecary and 
are to be used with as much care. This is an addi- 
tional reason for producing them by legitimate 
means from the food itself, and not by adding the 



58 



THE CHEMISTRY OF 



Chemistry of 
Flavors. 



Condiments 
and their 
Effect. 



crude materials in quantities relatively enormous to 
those of the food substances. 

The chemistry of cooking is therefore largely the 
chemistry of flavor-production — the application of 
heat to the food material in such a way as to bring 
about the right changes and only these. 

The flavors produced by cooking, correctly done, 
will be delicate and unobtrusive. Usually, except 
for broiled meats, a low heat applied for a long 
time, with the use of closed cooking vessels, de- 
velops the best flavors; while quick cooking, which 
necessitates a high temperature, robs the fine prod- 
ucts of nature's laboratory of their choicest ele- 
ments. Present American cookery, especially, sins 
in this respect. Either the food is insipid from lack 
of flavor or crudely seasoned at the last moment. 

The secret of the success of our grandmothers' 
cooking lay not solely in the brick oven — in the 
low, steady heat it furnished — but in the care, 
thought, and infinite pains they put into the prep- 
aration of their simple foods. Compared with 
these, the "one-minute" cereals, the "lightning" 
pudding mixtures of the present are insipid, or 
tasteless. Experience with the Aladdin Oven is an 
education in flavor production. 

Another source of stimulating flavor is found in 
the addition of various substances called Condi- 
ments. These consist of materials, of whatever 



COOKING AND CLEANING. 59 

nature, added to the food compounds, to give them 
a relish. Their use is legitimate ; their abuse, harm- 
ful. The effect of flavors is due to the stimulation 
of the nerves of taste and smell. Condiments should 
be used in a way to cause a like stimulation of the 
nerves. If they are added to food materials before 
or during the cooking process, a small quantity 
imparts a flavor to the entire mixture. If added to 
the cooked food, a larger quantity is used and the 
effect lasts, not only while the food is in contact 
with the nerves of the mouth, but also throughout 
the digestive tract, causing an irritation of the 
mucous membranes themselves. The tissues be- 
come weakened, and, in time, lose the power of 
normal action. 

Cayenne pepper directly applied to the food, 
although sometimes a help, is oftener the cause in 
dyspepsia. Highly seasoned food tends to weaken 
the digestion in the end, by calling for more secre- 
tion than is needed and so tiring out, as it were, 
the glands. It is like the too frequent and violent 
application of the whip to a willing steed — by and 
by he learns to disregard it. Just enough to accom- 
plish the purpose is nature's economy. 

This economy is quick to recognize and be satis- 
fied with a food which is easily digested without im- 
pairing the functional powers of the digestive 
fluids. A child seldom shows a desire for condi- 



60 



THE CHEMISTRY OF 



ments unless these have been first unwisely added 
by adults. Flavors are largely odors, or odors and 
tastes combined, and act upon the nervous system 
in a natural way. Condiments, in many cases, are 
powerful, stimulating drugs, exciting the inner lin- 
ings of the stomach to an increased and abnormal 
activity. Medicinally they may act as tonics. The 
skill of the cook consists in steering between the 
two digestion possibilities — hinder and help. 

Some relish-giving substances, as meat extracts, 
the caffeine of coffee, theine of tea, theo-bromine of 
cocoa, and alcohol of wines go directly into the 
blood and here act upon the nervous system. They 
quicken the circulation and, therefore, stimulate to 
increased activity. The cup of coffee thus drives 
out the feeling of lassitude from wearied nerves and 
muscles. Wine should never be treated as an arti- 
cle of diet, but as a Gennss-Mittel. 

The secret of the cooking of vegetables is the 
judicious production of flavor. In this the 
French cook excels. She adds a little meat juice to 
the cooked vegetables, thus obtaining the desired 
flavor with the cheaper nutritious food. This wise 
use of meats for flavor, while the actual food value 
is made up from the vegetable kingdom, is an im- 
portant item in public kitchens, institutions, or 
wherever expense must be closely calculated. 

In the study of economy, flavor-creation is of the 



COOKING AND CLEANING. 61 

utmost importance. In foods, as everywhere, 
science and art must supplement the purse, making 
the few and cheaper materials necessary for nutri- 
tion into a variety of savory dishes. Without the 
appetizing flavor, many a combination of food ma- 
terials is utterly worthless, for this alone stimu- 
lates the desire or appetite, the absence of which 
may prevent digestion. Food which pleases the 
palate, unless this has been abnormally educated, 
is usually wholesome, and judgment based on 
flavor is normally a sound one. 

Starch may be cooked according: to the most ap- Conditions 

J ° r for Digestion. 

proved methods; but, if there is no saliva, the starch 
is without food value. The piece of meat may be 
done to a turn; but, if there is no gastric juice in 
the stomach, it will not be dissolved, and hence is 
useless. A homely illustration will best serve 
our turn, — a cow may retain her milk by 
force of will. It is well known how much 
a contented mind has to do with her readi- 
ness to give milk and the quantity of 
milk she will yield. The various glands of the 
human body seem to have a like action. The dry 
mouth fails to moisten the food, and the stimulating 
flavor is lost. On the other hand the mouth 
"waters," and food is soon digested. The cow may 
be utterly foolish and whimsical in her ideas — so 
may persons. There may not be the least reason 



62 



THE CHEMISTRY OF 



Serving 



Discretion in 
Cooking. 



Bacterial 
Action Pro- 
duces 
Flavors. 



Cooking an 
Art. 



why a person should turn away from a given food, 
but if he does ? He suffers for his whims. 

Hence the cook's art is most important, for its 
results must often overcome adverse mental con- 
ditions by nerve-stimulating flavors. The art 
of serving, though out of place here, should be at- 
tentively studied with the effect on the appetite 
especially in view. This is of the utmost im- 
portance in connection with hospital cooking. 

Specific flavors, though agreeable in themselves, 
should be used with discretion. In Norway, the 
salmon is designedly cooked so as not to retain 
much of its characteristic savor, for this is too de- 
cided a flavor for an article of daily diet. In soups 
and stews a "bouquet" of flavors is better than the 
prominence of any one, although certain favorite 
dishes may have a constant flavor. 

Nature has produced many flavors and guarded 
well the secret of their production; but science is 
fast discovering their sources, as bacterial life and 
action are better understood. Now, the "June 
flavor" of butter may be produced in December, 
by inoculating milk with the right "butter 
bacillus." 

Cooking has thus become an art worthy the at- 
tention of intelligent and learned women. The 
laws of chemical action are founded upon the laws 
of definite proportions, and whatever is added more 



COOKING AND CLEANING. 63 

than enough, is in the way. The head of every 
household should study the condition of her fam- 
ily, and tempt them with dainty dishes, if that is 
what they need. Let her see to it that no burst of 
ill temper, no sullen disposition, no intemperance 
of any kind be caused by her ignorance or her dis- 
regard of the chemical laws governing the reactions 
of the food she furnishes. 

When this science and this art takes its place be- 
side the other sciences and other arts, one crying 
need of the world will be satisfied. 

We have now considered the three classes of 
food in one or more of which all staple articles of 
diet may be placed — the carbohydrates (starch and 
sugar), the fats and the nitrogenous material. Some 
general principles of diet, indicated by science, re- 
main to be discussed. 

Diet. 

All preparation of food-stuffs necessary to make v°T- es °* 
them into suitable food for man comes under the Saliva - 
head of what has been called "external digestion. 1 " 
The processes of internal digestion begin in the 
mouth. Here the saliva not only lubricates the 
finely divided portions of the food materials, but, 
in the case of starch, begins the process of chang- 
ing the insoluble starch into a soluble sugar. This 
process is renewed in the small intestine. The fats 



64 



THE CHEMISTRY OF 



Mastication. 



Pepsin and 
Acid of 
Stomach. 



Decomposi- 
:ion Products. 



are emulsified in the small intestine, and, with the 
soluble carbohydrates, are here largely absorbed. 

All the chemical changes which the nitrogenous 
food stuffs undergo are not well understood. Such 
food should be finely comminuted in the mouth, 
because, as before stated, chemical action is rapid 
in proportion to the fineness of division; but it is 
in the stomach that the first chemical change 
occurs. 

The chief agents of this change are pepsin 
and related substances, aided by the acid of the 
gastric juice; these together render the nitrogenous 
substance soluble and capable of passing through 
the membranes. Neither seems able to do this 
alone, for if the acid is neutralized, action ceases; 
and if pepsin is absent, digestion does not take 
place. 

Decompositions of a very complex kind occur, 
peptones are formed which are soluble compounds, 
and the nitrogen finally passes out of the system as 
urea, being separated by the kidneys, as carbon di- 
oxide is separated by the lungs. 

One of the most obvious questions is: Which is 
bestforhuman food — starch or fat, beans and peas, 
or flesh? As to starch or fat, the question has been 
answered by experience, and science has only tried 
to explain the reason. The colder the climate, the 
more fat the people eat. The tropical nations live 



COOKING AND CLEANING. 



65 



chiefly on starchy foods, as rice. From previous 
statements it will be seen that this is right in princi- 
ple. Fat yields more heat than rice; therefore the 
inference is plain that in the cold of winter fat is 
appropriate food, while in the heat of summer rice 
or some other starchy food should be substituted. 

The diet of summer should also contain much 
fruit. Increased perspiration makes necessary an 
increased supply of water. This may be furnished 
largely by fruits, and with the water certain acids 
are taken which act as correctives in the digestive 
processes. 

No evident rule can be seen in the case of the 
albuminous foods. At most, the class can be di- 
vided into three groups. The first includes the ma- 
terial of vegetable origin, as peas, lentils, and the 
gluten of wheat. The second comprises the white 
of egg and the curd of milk — material of animal 
origin. The third takes in all the animal flesh used 
by mankind as food. 

Considering the question from a purely chemical 
standpoint, without regarding the moral or social 
aspects of the case, two views stand out clearly: 
ist. If the stored-up vegetable matter has required 
the force derived from the sun to prepare it, the 
tearing apart and giving back to the air and earth 
the elements of which it was built up will yield the 
same amount of force to whatever tears it down; 



Seasonable 
Diet. 



Economy of 
a Mixed 
Diet. 



THE CHEMISTRY OF 



but a certain amount of energy must be used up in 
this destruction. 2d. If the animal, having accom- 
plished the decomposition of the vegetable and ap- 
propriated the material, is killed, and the prepared 
nitrogenous food in the form of muscle is eaten by 
man, then little force is necessary to render the 
food assimilable; it is only to be dissolved in order 
that it may enter into the circulation. The force- 
producing power is not lost; it is only transferred 
to another animal body. Hence the ox or the 
sheep can do a part of man's work for him in pre- 
paring the vegetable food for use, and man may 
thus accomplish more than he otherwise could. 
This digestion of material outside of the body is 
carried still further, by man, in the manufacture of 
partially digested foods, — "malted," "peptonized," 
"pre-digested," etc. Exclusive use of these is 
fraught with danger, for the organs of digestion 
lose power, if that which they have, however 
little, be long unused. 

Nearly all, if not all, young animals live on food 
of animal origin. The young of the human race 
live on milk; but it has been found by experience 
that milk is not the best food for the adult to live 
upon to the exclusion of all else. It is not con- 
ducive to quickness of thought or general bodily 
activity. 

Experience leads to the conclusion that mankind 



COOKING AND CLEANING. 6? 

needs some vegetable food. Two facts sustain this 
inference. The digestive organs of the herbivorous 
animals form fifteen to twenty per cent of 
the whole weight of the body. Those of 
the carnivorous animals form five to six 
per cent, those of the human race, about 
eight per cent. The length of the canal 
through which the food passes varies in about the 
same ratio in the three classes. A mixed diet seems 
to be indicated as desirable by every test which has 
been applied; but the proportions in which the 
vegetable and animal food are to be mingled, as 
well as the relative quantities of carbonaceous and 
nitrogenous material which will give the best effi- 
ciency to the human machine are not so easily 
determined. 

Nature seems to have made provision for the ex- Water and 
cess of heat resulting from the oxidation of too 
much starch or fat, by the ready means of evapora- 
tion of water from the surface; this loss of water 
being supplied by drinking a fresh supply, which 
goes, without change, into the circulation. The 
greater the heat, the greater the evaporation ; hence 
the importance of water as an article of diet, espe- 
cially for children, must not be overlooked. For 
an active person, the supply has been estimated at 
three quarts per day. Water is the heat regulator 
of the animal body. An article entitled " Water 



Air as Food. 



68 THE CHEMISTRY OF 

and Air as Food,"* by one of the authors of this 
book, treats this subject more thoroughly. 

While dangerous disease seldom results from 
eating an excess of starch or fat, because the por- 
tion not wanted is rejected as if it were so much 
sand, many of the most complicated disorders do 
result from an excess of nitrogenous diet. 

The readiness with which such substances under- 
go putrefaction, and the many noxious products to 
which such changes give rise, should lead us to be 
more careful as to the quantity of this food. 

From experiments made by the best investiga- 
tors, it seems probable that only one third of the 
estimated daily supply of food is available for ki- 
netic force; that is, that only about one third of the 
total energy contained in the daily food can be util- 
ized in digging trenches, carrying bricks, climbing 
mountains, designing bridges, or writing poems 
and essays. The other two thirds is used up in the 
internal work of the body — the action of the heart, 
lungs, and the production of the large amount of 
heat necessary to life. 

It has been estimated that a growing person 
needs about one part of nitrogenous food to four oi 
starch and fat; a grown person, one part nitro- 
genous to five or six of starch and fat. If this is 

♦Rumford Kitchen Leaflet, No. 6, American Kitchen Magazine, Vol. IV., 
257. 



COOKING AND CLEANING. 69 

true, then we may make out a life ration, or that 
amount of food which is necessary to keep the 
human machine in existence. 

For this climate, and for the habits of our people, 
we have estimated this life ration as approximately : 

Proteid. Fat. Carbohydrates. Calories. 

75 grams. 40 grams. 325 grams. 2,000. 

The amount of energy given out in the form of 
work cannot exceed the amount of energy taken in 
in the form of food ; so this life ration is increased 
to make a maximum and minimum for a work 
ration. For professional or literary persons the 
following may be considered a sufficient maximum 
and minimum: 



Proteid. 


Fat. 


Carbohydrates. 


Calories. 


i«5 grams. 


125 grams. 


450 grams. 


3»5oo. 


no grams. 


90 grams. 


420 grams. 


3,000. 



For hard manual labor about one-third is to be 
added to the above rations. An examination of the 
actual dietaries of some of the very poor who eat 
just enough to live, without doing any work, 
shows that in twelve cases the average diet was : 

Proteid. Fat. Carbohydrates. Calories. 

31 grams. 81 grams. 272 grams. 2 , 2 57« 

For further information on these points see the 
list of works at the end of this book. 

The first office of the food, then, is to keep the offices ot 
human body in a high condition of health; the 
second, to enable it to exert force in doing the work 



TO COOKING AND CLEANING. 

of the world; and a third, the value of which it is 
hardly possible to estimate, is to furnish an im- 
portant factor in the restoration of the body to nor- 
mal condition, when health is lost. In sickness, 
far more than in health, a knowledge of the right 
proportions of the essential food substances, and of 
the absolute quantity or food value given, is im- 
portant. How many a life has been lost because of 
a lack of this knowledge the world will never know. 



PART II. 
THE CHEMISTRY OF CLEANING. 



CHAPTER I. 
Dust. 



MANY a housewife looks upon dust as her in- 
veterate enemy against whom incessant war- 
fare brings only visible defeat. Between the battles, 
let us study the enemy — the composition of his 
forces, his tactics, his ammunition, in order that 
we may find a vantage ground from which to direct 
our assault, or from which we may determine 
whether it is really an enemy which we are fighting. 

The Century dictionary defines dust as "Earth, Definition of 
or other matter in fine dry particles so attenuated 
that they can be raised and carried by the wind." 
This suggests that dust is no modern product of 
the universe. Indeed, its ancestry is hidden in 
those ages of mystery before man was. Who can 
say that it does not reach to that eternity which can 
be designated only by "In the beginning?" 



72 THE CHEMISTRY OF 

Tyndall proved by delicate experiments £hat 
when all dust was removed from the track of a 
beam of light, there was darkness. So before the 
command "Let there be light," the dust-condition 
of light must have been present. Balloonists find 
that the higher they ascend the deeper the color of 
the sky. When at a distance of some miles, the 
sky is nearly black, there is so little dust to scatter 
the rays of light. If the stellar spaces are dustless, 
they must be black and, therefore, colorless. The 
moisture of the air collects about the dust-particles 
giving us clouds and, with them, all the glories of 
sunrise and sunset. Fogs, too, are considered to 
be masses of "water-dust," and ships far out at sea 
have had their sails colored by this dust, while sail- 
ing through banks of fog. Thinking, now, of the 
above definition, it may be said that the earth, in 
its final analysis, must be dust deposited during 
past ages; that to dust is due the light necessary 
to life, and that without it certain phenomena of 
nature — clouds, color, fog, perhaps, even rain and 
snow could not exist. 

It behooves us, then, as inhabitants of this dust- 
formed and dust-beautified earth to speak well of 
our habitation. We have found no enemy yet. 
The enemy must be lurking in the "other matter." 
This the dictionary says is in powdered form, car- 
ried by the air, and, therefore, at times existent in 



COOKING AND CLEANING. 



73 



it, as has been seen. A March wind gives sensible 
proof of this, but what about the quiet air, whether 
out of doors or in our houses? 

An old writer has said: "The sun discovers 
atonies, though they be invisible by candle-light, 
and makes them dance naked in his beams." Those 
sensible particles with these "atonies," which be- 
come visible in the track of a beam of light when- 
ever it enters a darkened room, make up the dust 
whose character is to be studied. 

Astronomers find meteoric dust in the atmos- 
phere. When this falls on the snow and ice fields 
of the Arctic regions, it is readily recognized. The 
eruption of Krakatoa proved that volcanic dust is 
disseminated world-wide. Dust contains mineral 
matter, also, from the wear and tear of nature's 
forces upon the rocks, bits of dead matter given off 
by animal and vegetable organisms, minute fibres 
from clothing, the pollen of plants, the dry and pul- 
verized excrement of animals. These constituents 
are easily detected — are they all? 

Let a mixture of flour and water stand out-of- 
doors, leave a piece of bread or bit of cheese on 
the pantry shelves for a week. The mixture fer- 
ments, the bread and cheese mold. Formerly, these 
changes were attributed to the "access of air" — i. e., 
to the action upon the substances, of the oxygen of 
the air; later experiments have proved that if the 



Visible and 

Invisible 

Dust. 



Composition 
of Dust 



Dust Plants. 



74 THE CHEMISTRY OF 

air be previously passed through a cotton-wool 
filter it will cause no change in the mixture. The 
oxygen is not filtered out, so it cannot be the cause 
of the fermentation. Now, all the phenomena of 
fermentation are known to be caused by minute 
vegetable organisms which exist everywhere in the 
air and settle from it when it becomes dry and still. 
They are molds, yeasts and bacteria. All are mi- 
croscopic and many sub-microscopic. They are 
found wherever the atmosphere extends — some 
feet below the surface of the ground and some 
miles above it, although on the tops of the 
highest mountains and, perhaps, far out at sea, 
the air is practically free from earthly dust, 
and therefore nearly free from these forms. The 
volcanic dust of the upper air does not appear to 
contain them. They are all spoken of as "germs," 
because they are capable of developing into grow- 
ing forms. All are plants belonging to the fungi; 
in their manner of life essentially like the plants 
we cherish, requiring food, growing, and repro- 
ducing their kind. They require moisture in order 
to grow or multiply; but, like the seeds of higher 
plants, can take on a condition calculated to resist 
hard times and endure these for long periods ; then 
when moisture is furnished, they immediately 
spring into growth. In the bacteria these spores 
are simply a resting stage and are not reproduc- 



COOKING AND CLEANING. 



75 



tive; while, in molds, they bring forth an active, 
growing plant. 

The common puff-ball (Ly coper don), the "smoke" 
ball of the country child, well illustrates both vege- 
tative and spore stages. This belongs to the fungi, 
is closely related to the molds, and consists of a 
spherical outer wall of two layers, enclosing tissues 
which form numerous chambers with membraneous 
partitions. Within these chambers are formed the 
reproductive cells or spores. When ripe, the mass 
becomes dry, the outer layer of the wall scales off, 
the inner layer splits open, allowing the minute dry 
spores to escape as a "cloud of dust." These are 
readily carried by the wind until caught on some 
moist spot favorable for their growth. They are 
found on dry, sandy soils, showing that very little 
moisture is needed; but when this is found, the 
spore swells, germinates, and grows into a new 
vegetative ball, which completes the cycle. 

Wheat grains taken from the wrappings of mum- 
mies are said to have sprouted when given moist- 
ure and warmth. Whether this be true or not, there 
can be no doubt that the vitality of some seeds and 
spores is wonderfully enduring. 

The spores of some of the bacteria may be boiled 
and many may be frozen — still life will remain. 

Aristotle declared that "all dry bodies become 
damp and all damp bodies which are dried engen- 



Spores. 



Vita Endur- 
ance. 



Dangerous 
Dust. 



•76 THE CHEMISTRY OF 

der animal life." He believed these dust germs to 
be animalcules spontaneously generated wherever 
the conditions were favorable. How could he, with- 
out the microscope, explain in any other way the 
sudden appearance of such myriads of living forms? 

Now, it is recognized that the air everywhere 
contains the spores of molds and bacteria, and it 
is this dust carried in the air which falls in our 
houses. This is our enemy. 

A simple housemaid once said that the sun 
brought in the dust "atomes" through the window, 
and the careful, old, New England housewife 
thought the same. So, she shut up the best room, 
making it dark and, therefore, damp. Unwittingly, 
she furnished to them the most favorable conditions 
of growth, in which they might increase at the rate 
of many thousands in twenty-four hours. 

"Let there be light" must be the ever-repeated 
command, if we would take the first outpost of the 
enemy. 

We live in an invisible atmosphere of dust, we 
are constantly adding to this atmosphere by the 
processes of our own growth and waste, and, finally, 
we shall go the way of all the earth, contributing 
our bodies to the making of more dust. Thus dust 
has a decided two-fold aspect of friendliness and 
enmity. We have no wish to guard ourselves 
against friends; so, for the present purposes, the 



COOKING AND CLEANING. 



7? 



inimical action of dust, as affecting the life and 
health of man, alone need challenge our attention. 
The mineral dust, animal waste, or vegetable 
debris, however irritating to our membranes, or 
destructive of our clothing, are enemies of minor 
importance, compared with these myriads of living 
germs, which we feel not, hear not, see not, and 
know not until they have done their work. 

From a sanitary point of view, the most im- Bacteria, 
portant of the three living ingredients of dust is 
that called bacteria. They are the most numerous, 
the most widely distributed, and perhaps the small- 
est of all living things. Their natural home is the 
soil. Here they are held by moisture, and by the 
gelatinous character caused, in large part, by their 
own vital action. When the surface of the ground 
becomes dry, they are earned from it, by the wind, 
into the air. Rain and snow wash them down; 
running streams take them from the soil; so that, at 
all times, the natural waters contain immense num- 
bers of them. They are heavier than the air and 
settle from it in an hour or two, when it is dry and 
still. They are now quietly resting on this page 
which you are reading. They are on the floor, the 
tops of doors and windows, the picture frames, in 
every bit of "fluff" which so adroitly eludes the 
broom — in fact, everywhere where dust can lodge. 

The second ingredient, in point of numbers, is Molds. 



78 THE CHEMISTRY OF 

the molds. They, too, are present in the air, both 
outside and inside of our houses; but being much 
lighter than the bacteria, they do not settle so 
quickly, and are much more readily carried into the 
air again, by a very slight breeze. 

The third, or wild yeasts, are not usually trouble- 
some in the air or in the dust of the house, where 
ordinary cleanliness rules. 

To the bacteriologist, then, everything is dirty 
unless the conditions for germ-growth have been 
removed, and the germs, once present, killed. 
All of this dirt cannot be said to be "matter in the 
wrong place," only when it is the wrong kind of 
matter in some particular place. The bacteria are 
Nature's scavengers. Every tree that falls in the 
forest — animal or vegetable matter of all kinds is 
immediately attacked by these ever-present, invisi- 
ble agents. By their life-processes, absorbing, se- 
creting, growing and reproducing, they silently 
convert such matter into various harmless sub- 
stances. They are faithful laborers, earning an 
honest living, taking their wages as they go. Their 
number and omnipresence show the great amount 
of work there must be for them to do. 

Then why should we enter the lists against such 
opponents? Because this germ-community is like 
any other typical community. 

The majority of the individuals are law-abiding, 



COOKING AND CLEANING. 79 

respectable citizens; yet in some dark corner a thief 
may hide, or a cut-throat steal in unawares. If 
this happens, property may be destroyed and life 
itself endangered. 

Molds, and some of the yeasts, destroy our prop- 
erty; but a certain few of the bacteria cause disease 
and death. In a very real sense, so soon as an or- 
ganism begins to live it begins to die ; but these are 
natural processes and do not attract attention so 
long as the balance between the two is preserved. 
When the vital force is lessened, by whatever cause, 
disease eventually shows itself. Methods for the 
cure of disease are as old as disease itself; but 
methods for the prevention of disease are of late 
birth. Here and there along the past, some minds, 
wiser than their age, have seen the possibilities of 
such prevention; but superstition and ignorance 
have long delayed the fruition of their hopes. 

"An ounce of prevention is worth a pound of Prevention of 
cure," though oft repeated has borne scanty fruit 
ini daily living. When the cause o-f smallpox, 
tuberculosis, diphtheria, typhoid fever, and other 
infectious diseases is known to be a living plant, 
which cannot live without food, it seems, at first 
sight, a simple matter to starve it out of existence. 
This has proved to be no simple nor easy task; so 
much the more is each person bound by the law 
of self-love and the greater law, "Thou shalt love 



Disease. 



80 THE CHEMISTRY OF 

thy neighbor as thyself," to do his part toward 
driving these diseases from the world. 

Any one of these dust-germs is harmless so long 
as it cannot grow. Prevent their growth in the 
human body, and the diseased condition cannot 
occur. 

Prevention, then, is the watchword of modern 
sanitary science. 

It may be asked: How do the germs cause dis- 
ease? 

Why do they not akvays cause disease? 

Numerous answers have been given during the 
short time the germ theory of infectious diseases 
has been studied. If we follow the history of this 
study, we may find, at least, a partial answer. 

A person is "attacked" by smallpox, diphtheria, 
lockjaw, typhoid fever, or some kindred disease. 
Common speech recognizes in the use of the word 
"attacked" that an enemy from outside has begun, 
by force, a violent onset upon the person. This 
enemy — a particular bacterium or other germ, has 
entered the body in some way. There may have 
been contact with another person ill with the same 
disease. The germ may have entered through food 
on which it was resting, by water, or by air as it 
touched the exposed flesh, where the skin was 
broken by a scratch or cut. It found in the blood 
or flesh the moisture and warmth necessary for its 



COOKING AND CLEANING. 81 

growth, and, probably, a supply of food at once de- 
sirable and bountiful. It began to feed, to grow, 
and to multiply rapidly, until the little one became 
a million. At this stage the patient knew he was 
ill. It was thoughf, at first, that the mere presence 
in the body of such enormous numbers caused the 
disease. 

Bacteria like the same kinds of food which we Food of 

. . Bacteria. 

like. Though they can and will live on starvation 
rations, they prefer a more luxurious diet. This 
fact led to the idea that they supplied their larder 
by stealing from the food supply of the invaded 
body; so that, while the uninvited and unwelcome 
guest dined luxuriously, the host sickened of starva- 
tion. This answer is now rejected. 

The food of the bacteria is not only similar in 
kind to our own food, but it must also undergo like 
processes of solution and absorption. 

Solution is brought about by the excretion of 
certain substances, similar in character and in ac- 
tion to the ferments secreted in the animal mouth, 
stomach and intestines. These excretions reduce 
the food materials to liquids, which are then ab- 
sorbed. 

The pathogenic or disease-producing germs are 
found to throw out during their processes of as- 
similation and growth, various substances which 
are poisons to the animal body, as are aconite and 



82 



THE CHEMISTRY OF 



digitalis. These are absorbed and carried by the blood 
throughout the entire system. These poisons are 
called toxines. It is now believed that it is these 
bacterial products, the toxines or poisons, which 
are the immediate cause of the diseased condition. 

Inoculation of some of the lower animals with 
the poisoned blood of a diseased person, in which 
blood no germ itself was present, has repeatedly 
produced the identical disease. It is far easier to 
keep such manufacturers out of the body than to 
"regulate" their manufactures after an entrance has 
been gained. 

These faint glimpses into the "Philosophy of 
Cleanness" lead to another question, namely: How 
shall we keep clean? 

The first requisite for cleanness is light — direct 
sunlight if possible. It not only reveals the visible 
dirt, but allies itself with us as an active agent 
towards the destruction of the invisible elements of 
uncleanness. That which costs little or nothing is 
seldom appreciated; so this all-abundant, freely- 
given light is often shut out through man's greed 
or through mistaken economy. The country dwell- 
er surrounds his house with evergreens or shade 
trees, the city dweller is surrounded by high brick 
walls. Blinds, shades, or thick draperies shut out 
still more, and prevent the beneficent sunlight from 
acting its role of germ-prevention and germ-de- 



COOKING AND CLEANING. 83 

struction. Bright-colored carpets and pale-faced 
children are the opposite results which follow. 
"Sunshine is the enemy of disease, which thrives in 
darkness and shadow." Consumption and scrofu- 
lous diseases are well-nigh inevitable, when blinds 
are tightly closed and trees surround the house, 
causing darkness, and, thereby, inviting dampness. 
As far as possible let the exterior of the house be 
bathed in sunlight. Then let it enter every nook and 
cranny. It will dry up the moisture, without which 
the tiny disease germs or other plants cannot grow; 
it will find and rout them by its chemical action. 
Its necessity and power in moral cleanness, who 
can measure? 

More plentiful than sunlight is air. We cannot Pure Air. 
shut it out entirely as we can light; but there is 
dirty air just as truly as dirty clothes and dirty 
water. The second requisite for cleanness, then, 
is pure air. 

Primitive conditions of human life required no Primitive 
thought of the air supply, for man lived in the open ; Life. 1 lons ° 
but civilization brings the need of attention and 
care for details; improvements in some directions 
are balanced by disadvantages in others; luxuries 
crowd out necessities, and man pays the penalty 
for his disregard of Nature's laws. Sunlight, pure 
air and pure water are our common birthright, 
which we often bargain away for so-called com- 
forts. 



84 



THE CHEMISTRY OF 



Products of 
Combustion. 



Air Pollution. 



Sunlight is purity itself. Man cannot contam- 
inate it, but the air about him is what man makes it. 
Naturally, air is the great "disinfectant, antiseptic 
and purifier, and not to be compared for a moment 
with any of artificial contrivance," but under man's 
abuse it may become a death-dealing breath. 

Charlemagne said: "Right action is better than 
knowledge ; but to act right one must know right." 
Nature's supply of pure air is sufficient for all, but 
to have it always in its pure state requires knowl- 
edge and constant, intelligent action. 

The gaseous products of the combustion carried 
on within our bodies; like products from our arti- 
ficial sources of heat and light — burning coal, gas 
and oil ; waste matters of life and manufactures car- 
ried into the air through fermentation and putre- 
faction — all these, with the innumerable sources of 
dust we have already found, load the air with im- 
purities. Some are quickly recognized by sight, 
smell or taste; but many, and these the more dan- 
gerous, are unrecognizable by any sense. They 
show their actions in our weakened, diseased and 
useless bodies. Dr. James Johnson says: "All 
the deaths resulting from fevers are but a drop in 
the ocean, when compared with the numbers who 
perish from bad air." 

The per cent of pollution in the country is much 
smaller than in the city, where a crowded popula- 



COOKING AND CLEANING. 85 

tion and extensive manufactories are constantly 
pouring forth impure matters, but by rapidly mov- 
ing currents, even this large per cent is soon diluted 
and carried away. Would that the air in country 
houses, during both winter and summer, might 
show an equally small per cent! 

Air is a real substance. It can be weighed. It Ah-aSub- 
will expand, and may be compressed like other 
gases. It requires considerable force to move it, 
and this force varies with the temperature. When 
a bottle is full of air, no more can be poured in. 
Our houses are full of air all the time. No more 
can come in till some has gone out. In breathing, 
we use up a little, but it is immediately replaced 
by expired air, which is impure. Were there no 
exits for this air, no pure air could enter, and we 
should soon die of slow suffocation. The better 
built the house the quicker the suffocation, unless 
special provision be made for a current of fresh air 
to push out the bad. Fortunately no house is air 
tight. Air will come in round doors and windows, 
but this is neither sufficient to drive out the bad 
nor to dilute it beyond harm. Therefore the air of 
all rooms must be often and completely changed, 
either by special systems of ventilation, or by in- 
telligent action in the opening of doors and win- 
dows. 

Sunlight and pure air are the silent but powerful Qelnness. 



86 COOKING AND CLEANING. 

allies of the housewife in her daily struggle toward 
the ideal cleanness, i. e., sanitary cleanness, the 
cleanness of health. Without these allies she may 
spend her strength for naught, for the plant-life of 
the quiet, dust-laden air will grow and multiply far 
beyond her powers of destruction. With these 
allies the victory over uncleanness might be easy 
and sure were dust alone the enemy to be fought; 
but the mixture of dust with greasy, sugary, or 
smoky deposits makes the struggle twofold. 



CHAPTER II. 



Dust Mixtures. 

Grease and Dust. 

THE various processes of housework give rise 
to many volatile substances. These, the vapors 
of water or fat, if not carried out of the house in 
their vaporous state will cool and settle upon all 
exposed surfaces, whether walls, furniture or fab- 
rics. This thin film entangles and holds the dust, 
clouding and soiling, with a layer more or less visi- 
ble, everything within the house. Imperfect ven- 
tilation allows additional deposits from fires and 
lights — the smoky products of incomplete com- 
bustion. 

Thorough ventilation is, then, a preventive meas- 
ure, which ensures a larger removal not only of the 
volatile matters, but also of the dust, with its possi- 
ble disease germs. 

Dust, alone, might be removed from most sur- 
faces with a damp or even with a dry cloth, or from 
fabrics by vigorous shaking or brushing; but, 
usually, the greasy or sugary deposits must first be 
broken up and, thus, the dust set free. This must be 
accomplished without harm to the material upon 



88 



THE CHEMISTRY OF 



Processes of 
Cleaning. 



Girease-Oils. 



\lkali Metals. 



which the unclean deposit rests. Here is a broad 
field for the application of chemical knowledge. 

Cleaning, then, involves two processes: First, 
the greasy film must be broken up, that the en- 
tangled dust may be set free. Second, the dust 
must be removed by mechanical means. Disinfec- 
tion sometimes precedes the second process, in or- 
der that the dangerous dust-plants may be killed 
before removal. 

To understand the methods of dust removal, it 
is necessary to consider the chemical character of 
the grease and, also, that of the materials effectual 
in acting upon it. 

Grease or fats, called oils when liquid at ordinary 
temperature, are chemical compounds made of dif- 
ferent elements, but all containing an ingredient 
known to the chemist as a fatty acid. 

The chemist finds in nature certain elements 
which, with the fatty acids, form compounds en- 
tirely different in character from either of the orig- 
inal ingredients. These elements are called the 
alkali metals and the neutral compounds formed by 
their union with the acid of the fat are familiarly 
known to the chemist as salts. 

The chemical group of "alkali metals" comprises 
six substances : Ammonium, Caesium, Lithium, Po- 
tassium, Rubidium and Sodium. Two of the six — 
Caesium and Rubidium — were discovered by means 



COOKING AND CLEANING. 89 

of the spectroscope, not many years ago, in the min- 
eral waters of Durckheim, and, probably, the total 
amount for sale of all the salts of these two metak 
could be carried in one's pocket. A third alkali 
metal — Lithium — occurs in several minerals, and 
its salts are of frequent use in the laboratory, but it 
is not sufficiently abundant to be of commercial 
importance. As regards the three remaining alkali 
metals, the hydrate of Ammonium (NHJOH, is 
known as "Volatile Alkali," the hydrates of Po- 
tassium, KOH, and Sodium, NaOH, as "Caustic 
Alkalies." With these three alkalies and their 
compounds, and these alone, are we concerned 
in housekeeping. The volatile alkali, Ammonia, is 
now prepared in quantity and price such that every 
housekeeper may become acquainted with its use. 
It does not often occur in soaps, but it is valuable 
for use in all cleansing operations — the kitchen, 
the laundry, the bath, the washing of woolens, and 
in other cases where its property of evaporation, 
without leaving any residue to attack the fabric or 
to attract anything from the air, is invaluable. The 
most extensive household use of the alkalies is in 
the laundry, under which head they will be more 
specifically described. 

Some of the fatty acids combine readily with Soaps. 
alkalies to form compounds which we call soaps. 
Others in contact with the alkalies form emulsions, 



90 



THE CHEMISTRY OF 



The Problem 
of Cleaning. 



Cleaning of 

Different 

Materials. 



" Finish " of 
Woods. 



so-called, in which the fatty globules are suspended, 
forming an opaque liquid. These emulsions are 
capable of being indefinitely diluted with clear 
water, and, by this means, the fatty globules are all 
carried away. Most of the fats are soluble in ben- 
zine, ether, chloroform, naphtha or alcohol. 

If the housekeeper's problem were the simple 
one of removing the grease alone, she would solve 
it by the free use of one of these solvents or by 
some of the strong alkalies. This is what the 
painter does when he is called to repaint or to re- 
finish; but the housewife wishes to preserve the 
finish or the fabric while she removes the dirt. She 
must, then, choose those materials which will dis- 
solve or unite with the grease without injury to the 
articles cleaned. 

The greasy film which entangles the unclean and 
possibly dangerous dust-germs and dust-particles 
is deposited on materials of widely different char- 
acter. These materials may be roughly divided 
into two classes: One, where, on account of some 
artificial preparation, the uncleanness does not 
penetrate the material but remains upon the sur- 
face, as on wood, metal, minerals, leather and some 
wall paper; the other, where the grease and dust 
settle among the fibres, as in fabrics. 

In the interior of the house, woods are seldom 
used in their natural -state.- The surface is covered 



COOKING AND CLEANING. 



91 



with two or more coatings of different substances 
which add to the wood durability or beauty. The 
finish used is governed by the character of the 
wood, the position and the purpose which it serves. 
The cleaning processes should affect the final coat 
of finish alone. 

Soft woods are finished with paint, stain, oil, 
shellac, varnish, or with two or more of these com- 
bined; hard woods with any of these and, in addi- 
tion, encaustics of wax, or wax with turpentine or 
oil. 

All these surfaces, except those finished with 
wax, may be cleaned with a weak solution of soap 
or ammonia, but the continued use of any such 
alkali will impair and finally remove the polish. 
Waxed surfaces are turned dark by water. Fin- 
ished surfaces should never be scoured nor cleaned 
with strong alkalies, like sal-soda or potash soaps, 
To avoid the disastrous effects of these alkalies the 
solvents of grease may be used or slight friction 
applied. 

Kerosene and turpentine are efficient solvents for 
grease and a few drops of these on a soft cloth may 
be used to clean all polished surfaces. The latter 
cleans the more perfectly and evaporates readily; 
the former is cheaper, safer, because its vapor is not 
so inflammable as that of turpentine, and it polishes 
a little while it cleans; but it evaporates so slowly 



Varnish, Oil, 
Wax. 



Solvents of 
Grease. 



92 THE CHEMISTRY OF 

that the surface must be rubbed dry each time, or 
dust will be collected and retained. The harder the 
rubbing, the higher the polish. 

Outside of the kitchen, the woodwork of the 
house seldom needs scrubbing. The greasy layer 
is readily dissolved by weak alkaline solutions, by 
kerosene or turpentine, while the imbedded dust is 
wiped away by the cloth. Polished surfaces keep 
clean longest. Strong alkalies will eat through the 
polish by dissolving the oil with which the best 
paints, stains or polishes are usually mixed. If the 
finish be removed or broken by deep scratches, the 
wood itself absorbs the grease and dust, and the 
stain may have to be scraped out. 

Woodwork, whether in floors, standing finish or 
furniture, from which the dust is carefully wiped 
every day, will not need frequent cleaning. A 
few drops of kerosene or some clear oil rubbed or 
with a second cloth will keep the polish bright and 
will protect the wood. 

Certain preparations of non-drying oils are now 
in the market, which, when applied to floors, serve 
to hold the dust and prevent its spreading through 
the room and settling upon the furnishings. They 
are useful in school-rooms, stores, etc., where the 
floor cannot be often cleaned. The dust and dirt 
stick in the oil and, in time, the whole must be 
cleaned off and a new coating applied. 



COOKING AND CLEANING. 93 

Many housewives fear to touch the piano, how- a clean 
ever clouded or milky the surface may become. 
The manufacturers say that pianos should be 
washed with soap and water. Use tepid water with 
a good quality of hard soap and soft woolen or cot- 
ton-flannel cloths. Wash a small part at a time, 
rinse quickly with clear water that the soap may 
not remain long, and wipe dry immediately. Do 
all quickly. A well-oiled cloth wiped over the sur- 
face and hard rubbing with the hand or with cham- 
ois will improve the appearance. If there are deep 
scratches which go through the polish to the wood, 
the water and soap should be replaced by rotten- 
stone and oil, or dark lines will appear where the 
alkali and water touched the natural wood. 

Painted surfaces, especially if white, may be Paint, 
cleaned with whiting, applied with a moistened 
woolen cloth or soft sponge. Never let the 
cloth be wet enough for the water to run or 
stand in drops on the surface. Wipe "with 
the grain" of the wood, rinse in clear 
water with a second soft cloth and wipe 
dry with a third. All washed surfaces should 
be wiped dry, for moisture and warmth furnish the 
favorable conditions of growth for all dust-germs, 
whether bacteria or molds. Cheese cloth may be 
used for all polished surfaces, for it neither scratches 
nor grows linty. 



94 THE CHEMISTRY OF 

Walls painted with oil paints may be cleaned 
with weak ammonia water or whiting in the same 
manner as woodwork; but if they are tinted with 
water colors, no cleaning can be done to them, for 
both liquids and friction will loosen the coloring 
matter. 

Waii-Paper. Papered walls should be wiped down with cheese 

cloth, with the rough side of cotton flannel, or some 
other soft cloth. This will effectually remove all 
free dust. Make a bag the width of the broom or 
brush used. Run in drawing strings. Draw the 
bag over the broom, and tie closely round the han- 
dle, just above the broom-corn. Wipe the walls 
down with a light stroke and the paper will not be 
injured. An occasional thorough cleansing will be 
needed to remove the greasy and smoky deposits. 
The use of bread dough or crumb is not recom- 
mended, for organic matter may be left upon the 
wall. A large piece of aerated rubber — the 
"sponge" rubber used by artists for erasing their 
drawings — may be used effectually, and will leave 
no harmful deposit. "Cartridge" paper may be 
scoured with fine emery or pumice powder, for the 
color goes through. Other papers have only a thin 
layer of color. 

Varnished and waxed papers are now made 
which may be washed with water. 

Leather. Leather may be wiped with a damp cloth or be 



COOKING AND CLEANING. 95 

kept fresh by the use of a little kerosene. An occa- 
sional dressing of some good oil, well rubbed in, 
will keep it soft and glossy. 

Marble may be scoured with fine sand-soap or Marble, 
powdered pumice, or covered with a paste of whit- 
ing, borax or pipe-clay, mixed with turpentine, 
ammonia, alcohol or soft soap. This should be left 
to dry. When brushed or washed off, the marble 
will be found clean. Polish with coarse flannel or 
a piece of an old felt hat. Marble is carbonate of 
lime, and any acid, even fruit juices, will unite 
with the lime, driving out the carbon dioxide, 
which shows itself in effervescence, if the quantity 
of acid be sufficient. Acids, then, should not touch 
marble, if it is desired to keep the polish intact. 
An encaustic of wax and turpentine is sometimes 
applied to marbles to give them a smooth, shining 
surface. 

Pastes of whiting, pipe-clay, starch or whitewash 
may be put over ornaments of alabaster, plaster and 
the like. The paste absorbs the grease and, by rea- 
son of its adhesive character, removes the grime 
and dust. 

Most metals may be washed without harm in a Metals, 
hot alkaline solution or wiped with a little kerosene. 
Stoves and iron sinks may be scoured with the 
coarser materials like ashes, emery or pumice ; but 
copper, polished steel, or the soft metals, tin, silver, 
and zinc require a fine powder that they may not 



96 THE CHEMISTRY OF 

be scratched or worn away too rapidly. Metal 
bathtubs may be kept clean and bright with whiting 
and ammonia, if rinsed with boiling hot water and 
wiped dry with soft flannel or chamois. 

Porcelain or soapstone may be washed like metal 
or scoured with any fine material. 

Glass of windows, pictures and mirrors may be 
cleaned in many ways. It may be covered with a 
whiting paste mixed with water, ammonia or alco- 
hol. Let the paste remain till dry, when it may be 
rubbed off with a sponge, woolen cloth or paper. 
Polish the glass by hard rubbing with news- 
papers or chamois. Alcohol evaporates more 
quickly than water and therefore hastens the 
process; but it is expensive and should not touch 
the sashes, as it might turn the varnish. Very good 
results are obtained with a tablespoonful of kero- 
sene to a quart of warm water. In winter, when 
water would freeze, windows may be wiped with 
clear kerosene and rubbed dry. Kerosene does not 
remove fly specks readily, but will take off grease 
and dust. A bag of coarsely woven cheese-cloth 
filled with indigo or other powdered blue may be 
dusted over glass. This, when rubbed hard with 
soft cloths or chamois, leaves a fine polish. 

Success in washing glass depends more upon 
manipulation than materials. It is largely a matter 
of patience and polishing. The outer surface of 



COOKING AND CLEANING. 97 

windows often becomes roughened by the dissolv- 
ing action of rain water, or milky and opaque by 
action between the sun, rain and the potash or soda 
in the glass. Ordinary cleaning will not make such 
windows clear and bright. The opaqueness may 
sometimes be removed by rubbing thoroughly with 
dilute muriatic acid. Then polish with whiting. 

Household fabrics, whether carpets, draperies Fabrics. 
or clothing, collect large quantities of dust, which 
no amount of brushing or shaking will entirely dis- 
lodge. They also absorb vapors which con- 
dense and hold the dust-germs still more firmly 
among the fibres. Here the fastness of color and 
strength of fibre must be considered, for a certain 
amount of soaking will be necessary in order that 
the cleansing material may penetrate through the 
fabric. In general, all fabrics should be washed 
often in an alkaline solution. If the colors will not 
stand the application of water, they may be cleansed 
in naphtha or rubbed with absorbents. The chem- 
istry of dyeing has made such progress during the 
last ten years that fast colors are more frequently 
found, even in the cheaper grades of fabrics, than 
could be possible before this time. It is now more 
a question of weak fibre than of fleeting color. 
Heavy fabrics may therefore be allowed to soak 
for some time in many waters, or portions of naph- 
tha, being rinsed carefully up and down without 



98 



THE CHEMISTRY OF 



Inflammable 
Materials. 



Prevention of 
Dirt. 



rubbing. All draperies or woolen materials should 
be carefully beaten and brushed before any other 
cleaning is attempted. Wool fabrics hold much of 
the dirt upon their hook-like projections, and these 
become knotted and twisted by hard rubbing. If 
the fabric be too weak to be lifted up and down in 
the liquid bath, it may be laid on a sheet, over a 
folded blanket, and sponged on both sides with the 
soap or ammonia solution or with the naphtha. If 
the colors are changed a little by the alkalies, rinse 
the fabrics in vinegar or dilute acetic acid ; if affect- 
ed by acids, rinse in ammonia water. 

In the use of naphtha, benzine, turpentine, etc., 
great caution is necessary. The vapor of all these 
substances is extremely inflammable. They should 
never be used where there is any fire or light pres- 
ent, nor likely to be for several hours. A bottle 
containing one of them should never be left un- 
corked. Whenever possible, use them out-of- 
doors. 

With both dust and grease, prevention is easier 
than removal. If the oily vapors of cooking and 
the volatile products of combustion be removed 
from the kitchen and cellar, and not allowed to dis- 
sipate themselves throughout the house, the greasy 
or smoky deposits will be prevented and the re- 
moval of the dust-particles and dust-plants will be- 
come a more mechanical process. Such vapors 



COOKING AND CLEANING. 00 

should be removed by special ventilators or by win- 
dows open at the top, before they become con- 
densed and thus deposited upon everything in the 
house. Let in pure air, drive out the impure; fill 
the house with sunshine that it may be dry, and the 
problem of cleanness is largely solved. 

fLofC. 



Grease. 



T 



CHAPTER III. 
Stains, Spots, Tarnish. 

'HESE three classes include the particular de- 
posits resulting from accident, careless- 
ness, or the action of special agents, as the 
tarnish on metals. They are numerous in char- 
acter, occur on all kinds of materials and their re- 
moval is a problem which perplexes all women 
and which requires considerable knowledge and 
much patience to solve. A few suggestions may 
help some one who has not yet found the best 
way for herself. 

Grease-spots. Grease seems to be the most common cause of 

such spots. Small articles that can be laundered 
regularly with soap and water, give little trouble. 
These will be discussed in the following chapter. 

Absorbents of Spots of grease on carpets, heavy materials, or 

colored fabrics of any kind which cannot be con- 
veniently laundered, may be treated with absorb- 
ents. Heat will assist in the process by melting 
the grease. Fresh grease spots on such fabrics 
may often be removed most quickly by placing 
over the spot a piece of clean white blotting paper 
or butcher's wrapping paper, and pressing the spot 
with a warm iron. It is well to have absorbent 



COOKING AND CLEANING. 101 

paper or old cloth under the spot as well. Heat 
sometimes changes certain blues, greens and reds, 
so it is well to work cautiously and hold the iron 
a little above the goods till the effect can be noted. 

French chalk, — a variety of talc, or magnesia, 
may be scraped upon the spot and allowed to re- 
main for some time, or applied in fresh portions, 
repeatedly. If water can be used, chalk, fuller's 
earth or magnesia may be made into a paste with 
it or with benzine and this spread over the spot. 
When dry, brush the powder off with a soft brush. 

For a fresh spot on fabrics of delicate texture or 
color, when blotting paper is not at hand, a 
visiting or other card may be split and 
the rough inner surface rubbed gently over the 
spot. Slight heat under the spot may hasten the 
absorption. Powdered soapstone, pumice, whit- 
ing, buckwheat flour, bran or any kind of coarse 
meal are good absorbents to use on carpets or up- 
holstery. They should be applied as soon as the 
grease is spilled. Old spots will require a solvent 
and fresh ones may be treated in the same way. 

Grease, as has been said, may be removed in Solvents of 

. . . Grease. 

three ways, by forming a solution, an emulsion, 
or a true soap. Wherever hot water and soap can 
be applied, the process is one of simple emulsion, 
and continued applications should remove both 
the grease and the entangled dust; but strong 



102 THE CHEMISTRY OF 

soaps ruin some colors and textures. Ammonia 
or borax may replace the soap, still the water may 
affect the fabric, so the solvents of grease are safer 
for use. Chloroform, ether, alcohol, turpentine, 
benzine and naphtha, all dissolve grease. In their 
commercial state some of these often contain im- 
purities which leave a residue, forming a dark ring, 
which is as objectionable as the original grease. 
Turpentine is useful for coarser fabrics, while 
chloroform, benzine and naphtha are best for silks 
and woolens. Ether or chloroform can usually 
be applied to all silks, however delicate. If 
pure, they are completely volatile and sel- 
dom affect colors. Whenever these solvents 
are used, it is well to place a circle of some 
absorbent material, like flour, crumbs of bread, 
blotting paper or chalk around the spot to take up 
the excess of liquid. Then rub the spot from the 
outside toward the center to prevent the spreading 
of the liquid, to thin the edges, and, thus, to ensure 
rapid and complete evaporation. The cleansing 
liquid should not be left to dry of itself. 
The cloth should be rubbed dry, but very 
carefully, for the rubbing may remove the 
nap from woolen goods and, therefore, change 
the color or appearance. Apply the solvent 
with a cloth as nearly like the fabric to be 
cleaned, in color and texture, as possible, 



COOKING AND CLEANING. 103 

or, in general, use a piece of sateen, which does 
not grow linty. A white cloth may be put under 
the stain to serve not only as an absorber of the 
grease and any excess of liquid, but also to show 
when the goods is clean. It is well to apply all 
cleansing liquids and all rubbing on the wrong 
side of the fabric. None of these solvents can be 
used near a flame. 

The troublesome "dust spot" has usually a neg- "Dus^ 
lected grease spot for its foundation. After the 
grease is dissolved, the dust must be cleaned out 
by thorough rinsing with fresh liquid or by brush- 
ing after the spot is dry. 

Our grandmothers found ox- gall an efficient Ox-gaii. 
cleanser both for the general and special deposits. 
It is as effectual now as then and is especially good 
for carpets or heavy cloths. It may be used clear 
for spots, or in solution for general cleansing and 
brightening of colors. Its continued use for car- 
pets does not fade the colors as ammonia or salt 
and water is apt to do. 

Cold or warm grease on finished wood can be Grease-spots 

. on Wood. 

wiped off easily with a woolen cloth moistened 
in soapsuds or with a few drops of turpentine. 
Soap should never be rubbed on the cloth except, 
possibly, for very bad spots round the kitchen 
stove or table. Solutions of washing soda, potash, 
or the friction, that may be used safely on unfin- 



104 THE CHEMISTRY OF 

ished woods, will take out the grease but will also 
destroy the polish. 

Hot grease usually destroys the polish and 
sinks into the wood. It then needs to be treated 
like grease on unfinished wood or scraped out 
with fine steel wool or wire fibre, sandpaper or 
emery paper. The color and polish must then be 
renewed. When hot grease is spilled on wood or 
stone, if absorbents are not at hand, dash cold 
water on it immediately. This will solidify the 
grease and prevent its sinking deeply into the ma- 
terial. 
Grease on Grease or oil stains on painted walls, wall-paper 

Wall-paperor r r r 

Leather. or leather, may be covered with a paste of pipe- 

clay, or French chalk and water. Let the paste 
dry and after some hours carefully brush off the 
powder. Sometimes a piece of blotting paper laid 
over the spot and a warm iron held against this, 
will draw out the grease. These pastes of absorb- 
ent materials are good for spots on marbles. They 
may then be mixed with turpentine or ammonia 
or soft soap. 

Paint - House paints consist mainly of oils and some 

colored earth. Spots of paint, then, must be 
treated with something which will take out the oil, 
leaving the insoluble coloring matter to be 
brushed off. When fresh, such spots may 
be treated with turpentine, benzine or naph- 



COOKING AND CLEANING. 105 

tha. For delicate colors or textures, chloroform 
or naphtha is the safest. The turpentine, un- 
less pure, may leave a resinous deposit. This 
may be dissolved in chloroform or benzine, but 
care should be exercised in the use of alcohol 
for it dissolves some coloring matters. Old paint 
spots often need to be softened by the application 
of grease or oil ; then the old and the new may be 
removed together. Whenever practicable, let all 
spots soak a little, that the necessity of hard rub- 
bing may be lessened. 

Paint on stone, bricks or marble, may be treated 
with strong alkalies and scoured with pumice 
stone or fine sand. 

Varnish and pitch are treated with the same vanish and 

. r . Pitch. 

solvents as paint — turpentine being the one in 
general use, — when the article stained will not 
bear strong alkalies. Pitch and tar usually need 
to be covered first with grease or oil, to soften 
them. 

Wax spots made from candles should be re- wax. 
moved by scraping off as much as possible, then 
treating the remainder with kerosene, benzine, 
ether, naphtha, or with blotting paper and a warm 
iron, as grease spots are treated. The soap and 
water of ordinary washing will remove slight 
spots. The spermaceti is often mixed with tallow 
which makes a grease spot, and with coloring mat- 
ters which may require alcohol. 



106 THE CHEMISTRY OF 

Spots made by food substances are greasy, sug- 
ary or acid in their character, or a combinatiuxi of 
these. That which takes out the grease will gen- 
erally remove the substance united with it, as the 
blood in meat juices. The sugary deposits are us- 
ually soluble in warm water. If the acids from 
fresh fruits or fruit sauces affect the color of the 
fabric, a little ammonia water may neutralize the 
acid and bring back the color. Dilute alcohol 
may sometimes be used as a solvent for colored 
stains from fruit. Blood requires cold or tepid 
water, never hot. After the red color is removed 
soap and warm water may be used. 

Blood stains on thick cloths may be absorbed 
by repeated applications of moist starch. 

Wheel-grease and lubricants of like nature are 
mixtures of various oils and may contain soaps or 
graphite. The ordinary solvents of the vegetable 
or animal oils will remove these mixtures from 
colored fabrics by dissolving the oil. The undis- 
solved coloring matter will, for the most part, pass 
through the fabric and may be collected on thick 
cloth or absorbent paper, which should always be 
placed underneath. From wash goods, it may be 
removed, readily, by strong alkalies and water, es- 
pecially if softened first by kerosene or the addition 
of more grease, which increases the quantity of 
soap made. Graphite is the most difficult of re- 
moval. 



COOKING AND CLEANING. 107 

Ink spots are perhaps the worst that can be en- ink. 
countered, because of the great uncertainty- of the 
composition of the inks of the present day. When 
the character of an enemy is known it is a compar- 
atively simple matter to choose the weapons to be 
used against him, but an unknown enemy must be 
experimented upon, and conquest is uncertain. 
Methods adapted to the household are difficult to 
find, as the effective chemicals need to be applied 
with considerable knowledge of proportions and 
effects. Such chemicals are often poisons and, 
in general, their use by unskilled hands is not to 
be recommended. 

Fresh ink will sometimes yield to clear cold 01 
tepid water. Skimmed milk is safe and often ef- 
fective. If the cloth is left in till the milk sours, 
the result is at times more satisfactory. This has 
proved effective on light colored dress goods 
where strong acids might have affected the colored 
printed patterns. Some articles may have a bit of 
ice laid over the stain with blotting paper under 
it to absorb the ink solution. Remove the satur- 
ated portions quickly and continue the process till 
the stain has nearly or quite disappeared. The last 
slight stain may be taken out with soap and water. 
Some colored dress goods will bear the applica- 
tion of hot tartaric acid or of muriatic acid, a drop 
at a time, as on white goods. 



108 THE CHEMISTRY OF 

Ink on carpets, table covers, draperies or heavy, 
dark cloths of any kind, may be treated immedi- 
ately with absorbents to keep the ink from spread- 
ing. Bits of torn blotting paper may be held at 
the surface of the spot to draw away the ink on 
their hairy fibres. Cotton-batting acts in the same 
way. Meal, flour, starch, sawdust, baking soda 
or other absorbents may be thrown upon the ink 
and carefully brushed up when saturated. If much 
is spilled, it may be dipped up with a spoon or 
knife, adding a little water to replace that taken 
up, until the whole is washed out. Then dry the 
spot with blotting paper. The cut surface of a 
lemon may be used, taking away the stained por- 
tion as soon as blackened. Usually it requires 
hard rubbing to remove the last of the stain. Car- 
pets may be rubbed with a floor brush, while a 
soft toothbrush may be used for more delicate ar- 
ticles. With white goods a solution of bleaching 
powder may be used, but there is always danger 
of rotting the fibres unless rinsing in ammonia 
water follow, in order that the strong acid of the 
powder may be neutralized. 

Fresh ink stains on polished woods may be 
wiped off with clear water, and old stains of some 
inks likewise yield to water alone. The black col- 
oring matter of other inks may be wiped off with 
the water, but a greenish stain may still remain 



COOKING AND CLEANING. 



109 



which requires turpentine. In general, turpentine 
is the most effectual remover of ink from polished 
woods. 

The indelible inks formerly owed their perman- 
ence to silver nitrate; now, many are made from 
aniline solutions and are scarcely affected by any 
chemicals. The silver nitrate inks, even after ex- 
posure to light and the heat of the sun or of a hot 
flat-iron, may be removed by bleaching liquor. 
The chlorine replaces the nitric acid forming a 
white silver chloride. This may be dissolved in 
strong ammonia or a solution of sodium hyposul- 
phite. Sodium hyposulphite, which may be 
bought of the druggists, will usually remove the 
silver inks without the use of bleaching fluid and is 
not so harmful to the fibres. Some inks contain 
carbon which is not affected by any chemicals. 

The aniline inks, if treated with chemicals may 
spread over the fabric and the last state be worse 
than the first. Other chemicals are effective with 
certain inks, but some are poisonous in themselves 
or in their products, some injure the fabric, and 
all require a knowledge of chemical reactions in 
order to be safely handled. Dried ink stains on 
silver, as the silver tops of inkstands may be 
moistened with chloride of lime and rubbed hard. 

Polished marble may be treated with turpen- 
tine, "cooking soda" or strong alkalies, remem- 



Indelible 
Inks. 



Aniline Inks, 



Marble. 



no 



THE CHEMISTRY OF 



bering that acids should never touch marble if it 
is desired to retain the polish. If the stain has 
penetrated through the polish, a paste of the alkali 
and turpentine may be left upon the spot for some 
time and then washed off with clear water. 

Sometimes the porcelain linings of hoppers 
and bowls become discolored with yellowish- 
brown stains from the large quantities of iron in 
the water supply. These should be taken off with 
muriatic acid. Rinse in clean water and, lastly, 
with a solution of potash or soda to prevent any 
injurious action of the acid on the waste pipes. 

Alcohol dissolves shellac. Most of the interior 
woodwork of the house, whether finish or furni- 
ture, has been coated with shellac in the process 
of polishing. If then, any liquid containing alco- 
hol, as camphor, perfumes, or medicines, be spilled 
upon such woodwork and allowed to remain, a 
white spot will be made, or if rubbed while wet, 
the dissolved shellac will be taken off and the bare 
wood exposed. 

Heat also turns varnish and shellac white. A 
hot dish on the polished table leaves its mark. 
These white spots should be rubbed with oil till the 
color is restored. 

If a little alcohol be brushed over the spot with 
a feather, a little of the surrounding shellac is dis- 
solved and spread over the stained spot. Hard 



COOKING AND CLEANING. 



Ill 



rubbing with kerosene will, usually, remove the 
spot and renew the polish. If the shellac be re- 
moved and the wood exposed the process of re- 
newal must be the original one of coloring, shellac- 
ing and polishing, until the necessary polish is ob- 
tained. 

Caustic alkalies, strong solutions of sal-soda, 
potash and the like, will eat off the finish. Apply 
sweet, olive, or other vegetable oils, in case of 
such accidents. The continued use of oils or al- 
kalies always darkens natural woods. 

The special deposits on metals are caused by the 
oxygen and moisture of the air, by the presence of 
other gases in the house, or by acids or corroding 
liquids. Such deposits come under the general 
head of tarnish. 

The metals, or their compounds, in common use 
are silver, copper and brass, iron and steel, tin, 
zinc and nickel. Aluminum is rapidly taking a 
prominent place in the manufacture of household 
utensils. 

There is little trouble with the general greasy 
film or with the special deposits on articles in daily 
use, if they are washed in hot water and soap, 
rinsed well and wiped dry each time. Yet certain 
articles of food act upon the metal of tableware 
and cooking utensils, forming true chemical salts. 
The salts of silver are usually dark colored and in- 



Alkalies. 



112 THE CHEMISTRY OF 

soluble in water or in any alkaline liquid which will 
not also dissolve the silver. Whether found in the 
products of combustion, in food, as eggs, in the 
paper or cloth used for wrapping, in the rubber 
band of a fruit jar, or the rubber elastic which may- 
be near the silver, sulphur forms with silver a gray- 
ish black compound — a sulphide of silver. All the 
silver sulphides are insoluble in water. Rub such 
tarnished articles, before washing, with common 
salt. By replacement, silver chloride, a white chem- 
ical salt, is formed, which is soluble in ammonia. 
If the article be not washed in ammonia it will soon 
turn dark again. Most of these metallic com- 
pounds formed on household utensils being insolu- 
ble, friction must be resorted to. 

The matron of fifty years ago took care of her 
silver herself or closely superintended its clean- 
ing, for the articles were either precious heirlooms 
or the valued gifts of friends. The silver of which 
they were made was hardened by a certain propor- 
tion of copper and took a polish of great brilliancy 
and permanence. The matron of to-day, who has 
the same kind of silver or who takes the same care, 
is the exception. Plated ware is found in most 
households. The silver deposited from the battery 
is only a thin coating of the pure soft metal — very 
bright when new, but easily scratched, easily tar- 
nished, and never again capable of taking a beauti- 



COOKING AND CLEANING. 113 

ful polish. The utensils, being of comparatively 
little value, are left to the table-girl to clean. She, 
naturally, uses the material which will save her 
labor. 

In order to ascertain if there was any foundation silver 
for the prevalent opinion that there was mercury or 
some equally dangerous chemical in the silver pow- 
ders commonly sold, samples were purchased in 
Boston and vicinity, and in New York and vicinity. 

Of the thirty-eight different kinds examined in 
1878 

25 were dry powder. 
10 " partly liquid. 
3 " soaps. 

Of the twenty-five powders, fifteen were chalk or 
precipitated calcium carbonate, with a little color- 
ing matter, usually rouge. 

6 were diatomaceous earth. 
2 " fine sand entirely. 
2 " fine sand partly. 

Mercury was found in none. No other injurious 
chemical was found in any save the "electro-plating 
battery in a bottle," which contained potassium 
cyanide, KCN, a deadly poison; but it was labeled 
poison, although the label also stated that "all salts 
of silver are poison when taken internally." This 
preparation does contain silver, and does deposit a 
thin coating, but it is not a safe article for use. 



114 



THE CHEMISTRY OF 



Of the nine polishes, partly liquid, five contained 
alcohol and ammonia for the liquid portion; four, 
alcohol and sassafras extract. The solid portion, in 
all cases, was chalk, with, in one case, the addition 
of a little jeweler's rouge. 

The caution to be observed in the use of these 
preparations is in regard to the fineness of the ma- 
terial. A few coarse grains will scratch the coat- 
ing of soft silver. Precipitated chalk, CaCO s , or 
well-washed diatomaceous earth, Si0 2 , seem to be 
of the most uniform fineness. 

We may learn a lesson in this, as well as in many 
other things, from the old-fashioned housewife. 
She bought a pound of whiting for twelve cents, 
sifted it through fine cloth, or floated off the finer 
portion, and obtained twelve ounces of the same 
material, for three ounces of which the modern 
matron pays twenty-five or fifty cents, according to 
the name on the box. 

The whiting may be made into a paste with am- 
monia or alcohol, the article coated with this and 
left till the liquid has evaporated. Then the pow- 
der should be rubbed off with soft tissue paper or 
soft unbleached cloth, and polished with chamois. 

Sometimes it is desirable to clean a large quantity 
of silverware at one time, but the labor of scouring 
and polishing each piece is considerable. They 
may all be placed carefully in a large kettle — a clean 



COOKING AND CLEANING. 



115 



wash-boiler is convenient for packing the large 
pieces — and covered wrth a strong solution of 
washing-soda, potash or borax. Boil them in this 
for an hour or less. Let them stand in the liquor 
till it is cold; then polish each piece with a little 
whiting and chamois. A good-sized piece of zinc 
boiled with the silverware will help to clean away 
any sulphides present, by replacing the silver in 
them and forming a white compound. 

Silver should never be rubbed with nor wrapped 
in woolen, flannel or bleached cloth of any kind, 
for sulphur is commonly used in bleaching proc- 
esses; nor should rubber in any form be present 
where silver is kept. The unused silyer may be 
wrapped in soft, blue-white or pink tissue paper, 
prepared without sulphur, and packed in un- 
bleached cotton flannel cases, each piece separately. 

Silver jewelry, where strong soap or other alkali 
is not sufficient for the cleaning process, may be 
immersed in a paste of whiting and ammonia, and 
when dry, brushed carefully with a soft brush. If 
there be a doubt as to the purity of the silver, re- 
place the ammonia by sweet oil or alcohol. The 
ammonia and whiting are also good for gold. Jew- 
elry cleaned with water may be dried in boxwood 
sawdust. 

Care is necessary in the use of ammonia in or on 
"silver'' topped articles, as vinaigrettes. These tops 



Protection of 
Silverware. 



Silver 
Jewelry. 



Copper and 
Silver. 



116 



THE CHEMISTRY OF 



Brass, Copper. 



Oxidation of 
Metals. 



are often made of copper with a thin layer of silver. 
Whenever the ammonia remains upon the copper, 
it dissolves it, forming poisonous copper salts. 

Brass and copper must not be cleaned with am- 
monia unless due care is taken that every spot be 
rinsed and wiped perfectly dry. Nothing is better 
for these metals than the rotten-stone and oil of old- 
time practice. These may be mixed into a paste at 
the time of cleaning or be kept on hand in quantity. 
Most of the brass polishes sold in the market are 
composed of these two materials, with a little alco- 
hol or turpentine or soap, to form an emulsion with 
the oil. Oxalic acid may be used to clean these 
metals, but it must be rinsed or rubbed off com- 
pletely, or green salts will be formed. Copper or 
brass articles cleaned with acids tarnish much more 
quickly from the action of moisture in the air than 
when cleaned with the oil and soft powder. Small 
spots may be removed with a bit of lemon juice and 
hot water. An occasional rubbing with kerosene 
helps to keep all copper articles clean and bright. 
Indeed, kerosene is useful on any metal, as well as 
on wood or glass. 

The presence of water always favors chemical 
change. Therefore iron and steel rapidly oxidize 
in damp air or in the presence of moisture. All 
metallic articles may be protected from such action 
by a thin oily coating. Iron and steel articles not in 
use may be covered with a thin layer of vaseline. 



COOKING AND CLEANING. 



117 



Rust spots may be scoured off with emery and 
oil covered with kerosene or sweet oil for some 
time and then rubbed hard, or in obstinate cases, 
touched with muriatic acid and then with ammonia, 
to neutralize the acid. 

A stove rubbed daily with a soft cloth and a few 
drops of kerosene or sweet oil may be kept black 
and clean, though not polished. Substances spilled 
on such a stove may be cleaned off with soap and 
water better than on one kept black with graphite. 

Nickel is now used in stove ornaments, in the 
bathroom, and in table utensils. It does not oxidize 
or tarnish in the air or with common use. It can 
be kept bright by washing in hot soap-suds and 
rinsing in very hot water. It may be rubbed with 
a paste of whiting and lard, tallow, alcohol or am- 
monia. 

Aluminum does not tarnish readily, and may be 
rubbed with the whiting or with any of the fine ma- 
terials used for silver. A paste is prepared by the 
dealers for this special use. 
> Kitchen utensils, with careful use, may be kept 
clean by soap and water or a liberal use of am- 
monia. Fine sand-soap must occasionally be used 
when substances are burned on or where the tin 
comes in contact with flame. Kerosene is a good 
cleaner for the zinc stove-boards; vinegar and 
water, if there is careful rinsing afterward, or a 
strong solution of salt and water may be used. 



Iron-rust. 



Care of 

Stoves. 



Nickel. 



Aluminum. 



Kitchen 
Utensils. 



CHAPTER IV. 

Laundry. 

THE health of the family depends largely upon 
the cleansing operations which belong to the 
laundry. Here, too, more largely perhaps than in 
any other line of cleaning, will a knowledge of 
chemical properties and reactions lead to econ- 
omy of time, strength and material. 

The numerous stains and spots on table linen 
and white clothes are dealt with in the laundry, 
and, also, all fabrics soiled by contact with the 
body. 

Body clothes, bed linen and towels become 
soiled not only by the sweat and oily secretions of 
the body, but also with the dead organic matter 
continually thrown off from its surface. Thus the 
cleansing of such articles means the removal of 
stains of varied character, grease and dust, and all 
traces of organic matter. 

The two most important agents in this purifica- 
tion are water and soap. , 

Pure water is a chemical compound of two 
gases, hydrogen and oxygen (H 2 0). It has great 
solvent and absorbent power, so that in nature 
pure water is never found, though that which falls 



COOKING AND CLEANING. 119 

in sparsely-settled districts, at the end of a long 
storm, may be approximately pure. The first fall 
of any shower is mixed with impurities which have 
been washed from the air. Among these may be 
acids, ammonia and carbon in the form of soot 
and creosote. It is these impurities which cause 
the almost indelible stain left when rain-water 
stands upon window-sills or other finished wood. 

Rain-water absorbs more or less carbon dioxide 
from various sources and, soaking into the soil, 
often comes in contact with lime, magnesia and 
other compounds. Water saturated with carbon 
dioxide will dissolve these substances, forming 
carbonates or other salts which are soluble, and 
such water is known as "hard." 

Water for domestic uses is called either "hard" Hard and 
or "soft" according as it contains a greater or less 
quantity of these soluble salts. When soap — a 
chemical compound — is added to hard water, it is 
decomposed by the water; and the new compound 
formed by the union of the lime with the fatty acid 
of the soap is insoluble and is deposited upon the 
surface of any articles with which it comes in con- 
tact, i. Therefore, large quantities of soap must be 
used before there can be any action upon the dirt. 
It has been estimated that each grain of carbonate 
of lime per gallon causes an increased expenditure 
of two ounces of soap per ioo gallons, and that 



120 THE CHEMISTRY OF 

the increased expense for soap in a household of 

five persons where such hard water is used, might 

amount to five or ten dollars yearly.* 

Temporary When the hardness is caused by calcium car- 

ana rerma- -' 

nent Hardness. bonate it is called "temporary" hardness, because 
it may be overcome by boiling. The excess of 
carbon dioxide is driven off and the lime precipi- 
tated. The same precipitation is brought about 
by the addition of sal-soda or ammonia. When 
the hardness is due to the sulphates of lime and 
magnesia, it cannot be removed by boiling or by 
the addition of an alkali; it is then known as "per- 
manent." 

Public water supplies are often softened before 
delivery to the consumers by the addition of 
slaked lime, which absorbs the carbon dioxide and 
the previously dissolved carbonate is precipitated. 
If this softening process be followed by filtration, 
the number of bacteria will be lessened, and the 
water, thereby, rendered still purer. 

All water for use with soap should, then, be 
naturally soft or made soft by boiling or by the 
addition of alkalies, ammonia or sal-soda. 

Soap - Another important material used in the laundry 

is soap. "Whether the extended use of soap be 
preceded or succeeded by an improvement in any 
community — whether it be the precursor or the re- 

* Water Supply, Wiiliam P. Mason, p. 366. 



COOKING AND CLEANING. 121 

suit of a higher degree of refinement among the 
nations of the earth — the remark of Liebig must 
be acknowledged to be true, that the quantity of 
soap consumed by a nation would be no inaccur- 
ate measure whereby to estimate its wealth and 
civilization. Of two countries with an equal 
amount of population, the wealthiest and most 
highly civilized will consume the greatest weight 
of soap. This consumption does not subserve sen- 
sual gratification, nor depend upon fashion, but 
upon the feeling of the beauty, comfort and wel- 
fare attendant upon cleanliness; and a regard to 
this feeling is coincident with wealth and civiliza- 
tion."* 

Many primitive people find a substitute for soap s a P substi- 
in the roots, bark or fruit of certain plants. Nearly 
every country is known to produce such vegetable 
soaps, the quality which they possess of forming 
an emulsion with oily substances being due to a 
peculiar vegetable substance, known as Saponin. 
Many of these saponaceous barks, roots and fruits 
are now used with good results — the "soap bark" 
of the druggist being one of the best substances 
for cleansing dress goods, especially black, wheth- 
er of silk or wool. 

The fruit of the soapberry tree — Papindus 
Saponaria — a native of the West Indies, is said to 

* Muspratt's Chemistry as Applied to A rts and Manufactures. 



tutes. 



122 



THE CHEMISTRY OF 



be capable of cleansing as much linen as sixty 
times its weight of soap. 

Wood ashes were probably used as cleansing 
material long before soap was made, as well as 
long after its general use. Their properties and 
value will be considered later. 

Soaps for laundry use are chiefly composed of 
alkaline bases, combined with fatty acids. Their 
action is "gently but efficiently to dispose the 
greasy dirt of the clothes and oily exudations of 
the skin to miscibility with, and solubility in wash 
water."* 

Oily matters, as we have seen, are soluble in cer- 
tain substances, as salt is soluble in water, and can 
be recovered in their original form from such solu- 
tions by simple evaporation. Others in contact 
with alkalies, form emulsions in which the sus- 
pended fatty globules make the liquid opaque, as 
in soapsuds. The soap is decomposed by water, 
the alkali set free acts upon the oily matter on the 
clothes, and unites with it, forming a new soap. 
The freed fatty acid remains in the water, causing 
the "milkiness," or is deposited upon the clothes. 

Certain compounds of two of the alkali metals, 
potassium and sodium, are capable of thus saponi- 
fying fats and forming the complex substances 
known as soaps. For the compounds of these al- 

* Chemistry applied to the Manufacture of Soaps and Candles. — Morfit. 



COOKING AND CLEANING. 123 

kalies employed in the manufacture of soap, we 
shall use the popular terms "potash" and "soda," as 
less likely to cause confusion in our readers' minds. 
Potash makes soft soap; soda makes hard soap. 
Potash is derived from wood ashes, and in the 
days of our grandmothers soft soap was the uni- 
versal detergent. Potash (often called pearlash) 
was cheap and abundant. The wood fires of every 
household furnished a waste product ready for its 
extraction. Aerated pearlash (potassium bicar- 
bonate), under the name of saleratus, was used for 
bread. Soda-ash was, at that time, obtained from 
the ashes of seaweed, and, of course, was not com- 
mon inland. 

The discovery by the French manufacturer, Le- 
blanc, of a process of making soda-ash from the 
cheap and abundant sodium chloride, or common 
salt, has quite reversed the conditions of the use 
of the two alkalies. Potash is now about eight 
cents a pound, soda-ash is only three. 

In 1824, Mr. Tames Muspratt, of Liverpool, first Manufacture 

J r r of Soda-ash. 

carried out the Leblanc process on a large scale, 
and he is said to have been compelled to give 
away soda by .he ton to the soap-boilers, before 
he could convince them that it was better than the 
ashes of kelp, which they were using on a small 
scale. The soap trade, as we now know it, came 
into existence after the soap-makers realized the 



124 THE CHEMISTRY OF 

value of the new process. Soda-ash is now the 
cheapest form of alkali, and housekeepers will do 
well to remember this fact when they are tempted 
to buy some new " ine" or "Crystal." 

In regard to the best form in which to use the 
alkali for washing purposes, experience is the best 
guide, — that is, experience reinforced by judg- 
ment; for the number of soaps and soap substi- 
tutes in the market is so great, and the names so 
little indicative of their value, that only general in- 
formation can be given. 

In the purchase of soap, it is safest to choose 
the make of some well-known and long-established 
firm, of which there are several who have a repu- 
tation to lose, if their products are not good; and, 
for an additional agent, stronger than soap, it is 
better to buy sal-soda or soda-ash (sodium car- 
bonate) and use it knowingly, than to trust to the 
highly-lauded packages of the grocery. 

Washing soda should never be used in the solid 
form, but should be dissolved in a separate vessel, 
and the solution used with judgment. The in- 
judicious use of the solid is probably the cause of 
the disfavor with which it is often regarded. One 
of the most highly recommended of the scores of 
"washing compounds" formerly in the market, 
doubtless owed its popularity to the following di- 
rections: "Put the contents of the box into one 



COOKING AND CLEANING. 125 

quart of boiling water, stir well, and add three 
quarts of cold water; this will make one gallon. 
For washing clothes, allow two cupfuls of liquid 
to a large tub of water." 

As the package contained about a pound of 
washing soda, this rule, which good housekeepers 
have found so safe, means about two ounces to a 
large tub of water, added before the clothes are 
put in. 

Ten pounds of washing soda can be purchased 
of the grocer for the price of this one-pound pack- 
age with its high-sounding name. Nearly all the 
compounds in the market depend upon washing 
soda for their efficiency. Usually they contain 
nothing else. Sometimes soap is present and, 
rarely, borax. In one or two, a compound of am- 
monia has been found. 

Ammonia may be used with soap or as its sub- Ammonia 
stitute. The ammonia ordinarily used in the house- 
hold is an impure article and its continued use yel- 
lows bleached fabrics. The pure ammonia may be 
bought of druggists or of dealers in chemical sup- 
plies and diluted with two or even four parts of 
water. Borax, where the alkali is in a milder form 
than it is in washing soda, is an effectual cleanser, 
disinfectant and bleacher. It is more expensive 
than soda or ammonia, but for delicate fabrics and 
for many colored articles it is the safest alkali in 
use. 



126 



THE CHEMISTRY OF 



Turpentine also is valuable in removing grease. 
A tablespoonful to a quart of warm water is a sat- 
isfactory way of washing silks and other delicate 
materials. It should never be used in hot water, 
for much would be lost by evaporation, and in this 
form it is more readily absorbed by the skin, caus- 
ing irritation and discomfort. 

Preparation for General Washing. 

White goods are liable to stains from a variety 
of sources. Many of these substances when acted 
upon by the moisture of the air, by dust, or al- 
kalies, change their character, becoming more or 
less indelible; colorless matters acquire color and 
liquids become semi-solid. All such spots and 
stains should be taken out before the clothes are 
put into the general wash to be treated with soap. 

Fruit stains are the most frequent and possibly 
the most indelible, when neglected. These should 
be treated when fresh. 

The juices of most fruits contain sugar in solu- 
tion, and pectose, a mucilaginous substance which 
will form jelly. All such gummy, saccharine mat- 
ters are dissolved most readily by boiling water, 
as are mucilage, gelatine and the like. To remove 
them when old, an acid, or in some cases, a 
bleaching liquid, like "chloride of lime" solution or 
Javelle water will be needed. 



COOKING AND CLEANING. 



127 



Stretch the stained part over an earthen dish and 
pour boiling water upon the stain until it disap- 
pears. How to use the acid and the Javelle water 
will be explained later on. 

Wine stains should be immediately covered 
with a thick layer of salt. Boiling milk is often 
used for taking out wine and fruit stains. 

Most fruit stains, especially those of berries, are 
bleached readily by the fumes of burning sulphur. 
S0 2 . These fumes are irritating to the mucous 
membrane and care should, therefore, be taken 
not to inhale them. Stand by an open window 
and turn the head away. Make a cone of stiff 
paper or cardboard or devote a small tin tunnel to 
this purpose. Cut off the base of the paper cone, 
leaving it level and have a small opening at the 
apex. On an old plate or saucer, place a small 
piece of sulphur, set it on fire, place over it the 
cone or tunnel, and hold the moistened stain over 
the chimney-like opening. Have a woolen cloth 
handy to put out the sulphur flame if the piece is 
larger than is needed. A burning match sometimes 
furnishes enough S0 2 for small spots. Do not get 
the burning sulphur on the skin. 

Medicine stains usually yield to alcohol. Iodine 
dissolves more quickly in ether or chloroform. 

Coffee, tea and cocoa stain badly, the latter, if 
neglected, resisting even to the destruction of the 



Medicine. 



128 THE CHEMISTRY OF 

fabric. These all contain tannin, besides various 
coloring matters. These coloring matters are 
"fixed" by soap and hot water. Clear boiling 
water will often remove fresh coffee and tea stains, 
although it is safer to sprinkle the stain with borax 
and soak in cold water first. (A dredging box 
filled with borax is a great convenience in the laun- 
dry.) Old cocoa and tea stains may resist the bo- 
rax. Extreme cases require extreme treatment. 
Place on such stains a small piece of washing- 
soda or "potash." Tie it in and boil the cloth for 
half an hour. It has already been said that these 
strong alkalies in their solid form cannot be al- 
lowed to touch the fabrics without injury. With 
this method, then, there must be a choice between 
the stain and an injury to the fabric, 
aveiie Water. An alkaline solution of great use and conven- 

ience is Javelle water. It will remove stains and 
is a general bleacher. This is composed of one 
pound of sal-soda with one-quarter pound of 
"chloride of lime" — calcium hypochlorite — in two 
quarts of boiling water. Let the substances dis- 
solve as much as they will and the solution cool and 
settle. Pour off the clear liquid and bottle it for 
use. Be careful not to let any of the solid portion 
pass into the bottle. Use the dregs to scour un- 
painted woodwork, or to cleanse waste pipes. 
When a spot is found on a white table-cloth, 



COOKING AND CLEANING. 129 

place under it an overturned plate. Apply Javelle 
water with a soft tooth-brush. (The use of a brush 
protects the skin and nails.) Rub gently till the 
stain disappears, then rinse in clear water and 
finally in ammonia. "Chloride of lime" always 
contains a powerful acid, as well as some free 
chlorine. 

Blood stains require clear, cold or tepid water, Blood, 
for hot water and soap render the red coloring 
matter less soluble. When the stain is brown and 
nearly gone, soap and hot water may be used. 

Meat juice on the table linen is usually com- 
bined with more or less fat. This also yields most 
readily to the cold water, followed by soap. 

Stains made by mucus should be washed in am- 
monia before soap is added. When blood is mixed 
with mucus, as in the case of handkerchiefs, it 
is well to soak the stains for some hours in a solu- 
tion of salt and cold water — two tablespoonfuls to 
a quart. Double the quantity of salt for heavier 
or more badly stained articles. The salt has a dis- 
infecting quality, and its use in this way is a wise 
precaution in cases of catarrh. 

Milk exposed to the air becomes cheesy, and Milk, 
hot water with milk makes a substance difficult of 
solution. Milk stains, therefore, should be washed 
out when fresh and in cold water. 

Grass stains dissolve in alcohol. If applied im- Grass. 



130 THE CHEMISTRY OF 

mediately, ammonia and water will sometimes 
wash them out. In some cases the following meth- 
ods have proved successful, and their simplicity 
recommends them for trial in cases where colors 
might be affected by alcohol. Molasses, or a paste 
of soap and cooking soda, may be spread over the 
stain and left for some hours, or the stain may be 
kept moist in the sunshine until the green color 
has changed to brown, then it will wash out in 
clear water. 

Mildew causes a spot of a totally different char- 
acter from any we have considered. It is a true 
mold, and like all plants requires warmth and 
moisture for its growth. When this necessary 
moisture is furnished by any cloth in a warm 
place, the mildew grows upon the fibres. During 
the first stages of its growth, the mold may be 
removed, but in time it destroys the fibres. 

Strong soapsuds, a layer of soft soap and pulver- 
ized chalk, or one of chalk and salt, are all effec- 
tive if, in addition, the moistened cloth be sub- 
jected to strong sunlight, which kills the plant 
and bleaches the fibres. Bleaching powder or 
Javelle water may be tried in cases of advanced 
growth, but success cannot be assured. 

Some of the animal and vegetable oils may be 
taken out by soap and cold water or dissolved in 
naphtha, chloroform, ether, etc. 



COOKING AND CLEANING. 131 

Some of the vegetable oils are only sparingly 
soluble in cold, but readily soluble in hot alcohol. 
The boiling point of alcohol is so low that care 
should be taken that the temperature be not raised 
to the ignition point. 

Mineral oil stains are not soluble in any alkaline 
or acid solutions. Kerosene will evaporate in time. 
Vaseline stains should be soaked in kerosene be- 
fore water and soap touch them. 

Ink spots on white goods are the same in charac- ink. 
ter as on colored fabrics. Many of the present inks 
are made from aniline or allied substances instead 
of the iron compounds of the past. Aniline black 
is indelible ; the colored anilines may be dissolved in 
alcohol. Where the ink is an iron compound the 
stain may be treated with oxalic, muriatic or hot 
tartaric acids, applied in the same manner as for 
iron-rust stains. No definite rule can be given, for 
some inks are affected by strong alkalies, others by 
acids, while some will dissolve in clear water. 

The present dyes are so much more stable than 
those of twenty-five years ago, that pure lemon 
juice or a weak acid like hydrochloric, has no effect 
upon many colors. Any acid should, however, be 
applied with caution. If the color is affected by 
acids, it may often be restored by dilute ammonia. 

The red iron-rust spots must be treated with acid. R^f iron- 
These are the result of true oxidation — the union 



rust. 



132 THE CHEMISTRY OF 

of the oxygen of the air with the iron in the pres- 
ence of moisture. The salt formed is deposited 
upon the fabric which furnishes the moisture. Or- 
dinary "tin" utensils are made from iron coated 
with tin, which soon wears off, so no moist fabric 
should be left long in tin unless the surface is entire. 

Iron-rust is, then, an oxide of iron. The oxides 
of iron, copper, tin, etc., are insoluble. The chlor- 
ides, however, are soluble. Replace the oxygen 
with the chlorine of hydrochloric acid and the iron 
compound will be dissolved. The method of apply- 
ing the acid is very simple. 

Fill an earthen dish two thirds full of hot water 
and stretch the stained cloth over this. Have near 
two other dishes with clear water in one and am- 
monia water in the other. The steam from the hot 
water will furnish the heat and moisture favorable 
for chemical action. Drop a little hydrochloric 
(muriatic) acid, HC1, on the stain with a medicine 
dropper. Let it act a moment, then lower the cloth 
into the clear water. Repeat till the stain disap- 
pears. Rinse carefully in the clear water and, 
finally, immerse in the ammonia water that any ex- 
cess of acid may be neutralized and the fabric pro- 
tected. 

Salt and lemon juice are often sufficient for a 
slight stain, probably because a little hydrochloric 
acid is formed from their union. 



COOKING AND CLEANING. 133 

Many spots appear upon white goods which re- Bluing, 
semble those made by iron-rust, or the fabrics 
themselves acquire a general yellowish tinge. This 
is the result of the use of bluing and soap, where 
there has been imperfect rinsing of the clothes. 
The old-time bluing was pure indigo. This is in- 
soluble, but, by its use, a fine blue powder was 
spread among the fibres of the cloth. It required 
careful manipulation, which it usually had. Indigo 
with- sulphuric acid can be made to yield a soluble 
paste. This is the best form of bluing which can 
be used, for a very little gives a dark, clear blue to 
water, and overcomes the yellowish tinge which 
cotton or linen will acquire in time unless well 
bleached by sunshine. The expense and difficulty 
of obtaining this soluble indigo has led to the sub- . 
stitution of numerous solid and liquid "blues" by 
the use of which the laundress is promised success 
with little labor. Most of these liquid bluings con- 
tain some iron compound. This, when in contact 
with a strong alkali, is broken up and the iron is 
precipitated. If, then, bluing be used where all the 
soap or alkali has not been rinsed from the clothes, 
this decomposition and precipitation takes place, 
and a deposit of iron oxide is left on the cloth. This 
must be dissolved by acid like any iron-rust. 
^ Some "blues" are compounds of ultramarine, a 
brilliant blue silicate of aluminum. These are gen- 



134 THE CHEMISTRY OF 

erally used in the form of a powder which is insol- 
uble, settles quickly and, thereby, leaves blue spots 
or streaks. It is very difficult to prevent these when 
insoluble powdered "blues" are used. This silicate 
combined with hydrochloric acid forms a jelly-like 
mass from which a white precipitate is formed. 
These ultramarine blues are sometimes recom- 
mended because of this white precipitate, obviating, 
as is said, the yellowish results of careless rinsing, 
inevitable when iron "blues" are used. The advice 
is misleading, for no precipitate is formed unless an 
acid be added. 

When solid bluing is used it should be placed in 
a flannel bag and stirred about in a basin of hot 
water. In this way only the finest of the powder is 
obtained. After this blued water is poured into the 
tub, it must be continually stirred, to prevent the 
powder from settling in spots or streaks upon the 
clothes. 
Bleaching. First, then, the removal of all dirt, and second, 

the removal, by thorough rinsing, of all soap or 
other alkalies used in the first process, and third, 
long exposure to air and sunshine should render 
the use of bluing unnecessary. The experience of 
many shows that clothes that have never been 
blued, never need bluing. In cities where conveni- 
ences for drying and bleaching in the sunshine are 
few, and where clear water or clear air are often un- 



COOKING AND CLEANING. 135 

attainable, a thorough bleaching two or three times 
a year is a necessity ; but in the country it is wiser to 
abolish all use of bluing and let the great bleacher, 
the sun, in its action with moisture and the oxygen 
of the air, keep the clothes white as well as pure. 

Freezing aids in bleaching, for it retains the 
moisture, upon which the sun can act so much the 
longer. The easiest household method of bleach- 
ing where clean grass, dew and sunshine are not 
available, is by the use of "bleaching powder." In 
the presence of water and weak acids, even carbonic 
acid, oxygen and chlorine are both set free from 
the compound. At the moment of liberation the 
action is very powerful. The organic coloring mat- 
ters present are seized upon and destroyed, thereby 
bleaching the fabric. 

Directions for the use of the powder usually ac- 
company the can in which it is bought. The woman 
who knows that the acid always present in the pow- 
der must be completely rinsed out or neutralized 
by an alkali, may use her bleaching powder with 
safety and satisfaction. 

All special deposits should be removed before General 
the general cleansing of the fabric is undertaken. 
Grease and other organic matters are the undesir- 
able substances which are to be disposed of in the 
general cleansing. Grease alone is more quickly 
acted upon by hot water than by cold, but other 



Cleansing. 



136 



THE CHEMISTRY OF 



" Yellowness." 



organic matter is fixed by the hot water. There- 
fore, while hot water melts the grease quickly, the 
mixture may be thus spread over the surface and 
may not be removed by the soap. 

An effective method, proved by many housewives 
of long experience, is to soap thoroughly the dirti- 
est portions of the clothes, fold these together 
toward the center, roll the whole tightly, and soak 
in cold water. The water should just cover the 
articles. In this way the soap is kept where it is 
most needed, and not washed away before it has 
done its work. When the clothes are unrolled the 
dirt may be washed out with less rubbing. 

Too long soaking when a strong soap is used, 
which has much free alkali, would weaken the fab- 
ric. Judgment, trained by experience must guide 
in such cases, so that effective cleaning depends 
upon careful manipulation. 

Whether to boil or not to boil the clothes de- 
pends largely upon the purity of the materials used 
and the degree of care exercised. Many persons 
feel that the additional disinfection which boiling 
ensures is an element of cleanness not to be disre- 
garded ; others think it unnecessary under ordinary 
conditions, while others insist that boiling yellows 
the clothes. 

The causes of this yellowness seem to be : 



COOKING AND CLEANING. 



137 



Impure materials in the soap used; 

The deposition, after a time, of iron from the 
water or the boiler; 

The imperfect washing of the clothes — that is, 
the organic matter is not thoroughly removed. 

The safest process seems to be to put the clothes 
into cold water with little or no soap, let the tem- 
perature rise gradually to the boiling point and 
remain there a few minutes. 

Soap is more readily dissolved by hot water than 
by cold, hence the boiling should help in the com- 
plete removal of the soap and may well precede the 
rinsing. 

Borax — A tablespoonful to every gallon of 
water — added to each boilerful serves as a bleacher 
and an aid in disinfection. The addition of the 
borax to the last rinsing water is preferred by 
many. In this case, the clothes should be hung out 
quite wet, so that the bleaching may be thorough. 

"Scalding," or the pouring of boiling water over 
the clothes is not so effectual for their disinfec- 
tion as boiling, because the temperature is so 
quickly lowered. 

The main points in laundry cleansing seem to 
be:— 

The removal of all stains; 

Soft water and a good quality of soap; 

The use of strong alkalies in solution only; 



Scalding. 



Necessities 
for Good 
Cleansing. 



138 



THE CHEMISTRY OF 



Not too hot nor too much water while the soap 
is acting upon the dirt; 

Thorough rinsing, that all alkali may be re- 
moved; 

Long exposure to sunlight — the great bleacher 
and disinfectant. 

The fibres of cotton, silk and wool vary greatly 
in their structure, and a knowledge of this struc- 
ture, as shown under the microscope, may guide 
to proper methods of treatment. 

The fibres of cotton, though tubular, become 
much flattened during the process of manufacture, 
and under the microscope show a characteristic 
twist, with the ends gradually tapering to a point. 
It is this twist which makes them capable of being 
made into a firm, hard thread. 

The wool fibre, like human hair, is marked by 
transverse divisions, and these divisions are ser- 
rated. These teeth become curled, knotted or 
tangled together by rubbing, by very hot water, or 
by strong alkalies. This causes the shrinking which 
should be prevented. When the two fibres are 
mixed there is less opportunity for the little teeth 
to become entangled and, therefore, there is less 
shrinkage. 

Linen fabrics are much like cotton, with slight 
notches or joints along the walls. These notches 
serve to hold the fibres closely together and enable 



COOKING AND CLEANING. 139 

them to be felted to form paper, Linen, then, will 
shrink, though not so much as wool, for the fibres 
are more wiry and the teeth much shorter. 

Silk fibres are perfectly smooth, and when silk. 
rubbed, simply slide over each other. This pro- 
duces a slight shrinkage in the width of woven 
fabrics. 

All wool goods, then, require the greatest care washing of 
in washing. The different waters used should be of 
the same temperature, and never too hot to be 
borne comfortably by the hand. 

The soap used should be in the form of a thin 
soap solution. No soap should be rubbed on the 
fabric, and only a good white soap, free from rosin, 
or a soft potash soap, is allowable. Make each 
water slightly soapy and leave a very little in the 
fabric at the end, to furnish a dressing as nearly 
like the original as possible. 

Many persons prefer ammonia or borax in place 
of the soap. For pure white flannel, borax gives the 
best satisfaction, on account of its bleaching qual- 
ity. Whatever alkali is chosen, care should be ex- 
ercised in the quantity taken. Only enough should 
be used to make the water very soft. 

The fibres of wool collect much dust upon their 
tooth-like projections, and this should be thor- 
oughly brushed or shaken off before the fabric 
is put into the water. All friction should be by 



140 



THE CHEMISTRY OF 



squeezing, not by rubbing. Wool should not be 
wrung by hand. Either run the fabric smoothly 
through a wringer or squeeze the water out, that 
the fibres may not be twisted. Wool may be well 
dried by rolling the article tightly in a thick dry 
towel or sheet and squeezing the whole till all 
moisture is absorbed. Wool should not be allowed 
to freeze, for the teeth will become knotted and 
hard. 

Linen, like wool, collects much dirt upon the 
surface which does not penetrate the fabric. Shake 
this off and rub the cloth as little as possible. 
Linen or woolen articles should not be twisted in 
the drying process, as it is sometimes impossible 
to straighten the fibres afterward. 

Colored cottons should have their colors fixed 
before washing. Salt will set most colors, but the 
process must be repeated at each washing. Alum 
sets the colors permanently, and at the same time 
renders the fabric less combustible, if used in 
strong solution after the final rinsing. 

Dish cloths and dish towels must be kept clean 
as a matter of health, as well as a necessity for 
clean, bright tableware. The greasy dish cloth 
furnishes a most favorable field for the growth 
of germs. It must be washed with soap and hot 
water and dried thoroughly each time. All such 
cloths should also form a part of the weekly 



COOKING AND CLEANING. 



141 



wash and be subjected to all the disinfection pos- 
sible, with soap, hot water and long drying in sun- 
shine and the open air. Beware of the disease- 
breeding, greasy and damp dish cloth hung in a 
warm, dark place! 

Oven towels, soiled with soot and crock, may be 
soaked over night, or for some hours, in just kero- 
sene enough to cover, then washed in cold water 
and soap. 

With very dirty clothes or for spots, where hard 
rubbing is necessary, much strength may be saved 
by using a scrubbing brush. 

Laundry tubs should be carefully washed and 
dried. Wooden tubs, if kept in a very dry place, 
and turned upside down, may have the bottoms 
covered with a little water. 

The rubber rollers of the wringer may be kept 
white by rubbing them with a clean cloth and a 
few drops of kerosene. 

All waste and overflow pipes, from that of the 
kitchen sink to that of the refrigerator, become 
foul with grease, lint, dust, and other organic mat- 
ters that are the result of bacterial action. They 
are sources of contamination to the air of the en- 
tire house and to the food supply, thereby endan- 
gering health. All bath, set-bowl and water closet 
pipes should be flushed generously once a day, at 
least, the kitchen sink pipe with clear boiling 



Care of Laun« 
dry Furni- 
ture. 



Care ol 
Plumbing. 



142 THE CHEMISTRY OF 

water; and once a week all pipes should have a 
thorough cleaning with a strong boiling solution 
of washing-soda and a monthly flushing with caus- 
tic potash. The plumbers recommend the "stone" 
or crude potash for the kitchen pipe. This is 
against their own interests, for many a plumber's 
bill is saved where the housewife knows the dan- 
ger and the means of prevention of a grease-coated 
sink drain. The pipe of the refrigerator should be 
cleared throughout its entire length with the soda 
solution. Avoid any injury to the metallic rims of 
the waste pipes by using a large tunnel. 

Old-fashioned styles of overflow pipes retain a 
large amount of filth, and it is very difficult to dis- 
lodge it. A common syringe may be devoted to 
this purpose. By its patient, frequent use even this 
tortuous pipe may be kept clean. 

Ideal Cleanness. 

Ideal cleanness requires the cleanness of the in- 
dividual, of his possessions, and of his environ- 
ment. Each individual is directly responsible for 
his personal cleanness and that of his possessions; 
but over a large part of his environment he has 
only indirect control. Not until direct personal 
responsibility is felt in its fullest sense, and exer- 
cised in all directions toward the formation and 
carrying out of sufficient public laws, will sanitary 



COOKING AND CLEANING. 



143 



cleanness supplant the cure of a large number of 
diseases by their prevention. 

Many of the diseases of childhood are directly 
traceable to uncleanness, somewhere. By these dis- 
eases the system is often so weakened that others 
of different character are caused which, though 
slow in action, may baffle all science in their cure. 

The necessity of forming systematic habits of 
cleanness in the young is the first step toward sani- 
tary health. They should, then, step by step, as 
they are able to grasp the reasons for the habits, 
be educated in all the sciences which give them 
the knowledge of the cause and effects of un- 
cleanness, the methods of prevention and removal, 
and the relation of all these to building laws and 
municipal regulations. 

The first environment to be kept clean is the 
home. But personal cleanness and household 
cleanness should not be rendered partially futile by 
unclean schoolhouses, public buildings and streets. 

The housekeeping of the schoolhouses, especially, 
should be carried on with a high regard to all 
hygienic details, since here the degree of danger 
is even greater than in the home. In public 
schoolhouses the conditions favorable to the pres- 
ence of disease germs abound. If present, their 
growth is rapid, and the extent of contagion be- 
yond calculation. The cooperation of all most in- 



Personal 
Cleanness. 



144 COOKING AND CLEANING. 

terested — pupils and teachers — should be expected 
and required as firmly as their cooperation in any- 
other department of education. 

The sanitary condition of every school building 
should be a model object lesson for the home; then, 
instruction in personal cleanness will carry the 
weight of an acknowledged necessity. 

Schoolhouses which are models of sanitary clean- 
ness will cause a demand for streets and public 
conveyances of like character; then all public build- 
ings will be brought under the same laws of evi- 
dent wisdom. 

Not till the right of cleanness is added to the 
right to be well fed, and both are assured to each 
individual by the knowledge and consent of the 
whole people, can the greater gospel of prevention 
make good its claims. 



CHAPTER V. 

The Housekeeper's Laboratory 

or 

The Chemicals For Household Use. 

THE thrifty housewife may not only save many 
dollars by restoring tarnished furniture and 
stained fabrics, but may also keep her belongings 
fresh and "as good as new," by the judicious use 
of a few chemical substances always ready at her 
hand. 

It is essential, however, that she know their 
properties and the effect they are likely to have on 
the materials to be treated, lest more harm than 
good result from their use. A good example is the 
instant disappearance of all red iron-rust stains 
when treated with a drop of hydrochloric acid (the 
muriatic acid of the druggist). If, however, the 
acid is not completely washed out, the fabric will 
become eaten, and holes will appear, which, in the 
housekeeper's eye, are worse than the stains. This 
danger may be entirely removed by adding am- 
monia to the final rinsing water, which neutralizes 
any remaining acid, and the stained tray-cloth or 
sheet is perfectly whitened. 

The chemicals for household use are chiefly 



146 THE CHEMISTRY OF 

acids, alkalies, and solvents for grease. Acids and 
alkalies are opposed to each other in their proper- 
ties, and if too much of either has been used, it 
may be rendered innocent, or neutralized by the 
other; as, when soda has turned black silk brown, 
acetic acid or vinegar will bring the color back. 

The acids which should be on the chemical shelf 
of the household are acetic, hydrochloric (muri- 
atic), oxalic, tartaric. Vinegar can be used in 
many cases instead of acetic acid; but vinegar con- 
tains coloring matters which stain delicate fabrics, 
and it is better to use the purified acid, especially 
as the so-called vinegar may contain sulphuric 
acid. 

Some bright blue flannels and other fabrics, 
when washed with soap or ammonia become 
changed or faded in color. If acetic acid or vin- 
egar be added to the last rinsing water, the orig- 
inal appearance may be restored. Not all shades 
of blue are made by the same compounds, hence 
not all faded blues can be thus restored. 

The use of these acids has been indicated in the 
previous pages, and there remains to be consid- 
ered, only certain cautions. Hydrochloric acid is 
volatile. It will escape even around a glass stop- 
per and will eat a cork stopper; therefore, either 
the glass stopper should be tied in with an im- 
pervious cover — rubber or parchment — or a rub- 



COOKING AND CLEANING. 147 

ber stopper used, for the escaping fumes will rust 
metals and eat fabrics. 

Oxalic acid should be labeled poison. 

The bleaching agents, "chloride of lime," cal- 
cium hypochlorite, sodium hypochlorite, sodium 
hyposulphite (thiosulphite), owe their beneficent 
effect to substances of an acid nature which are 
liberated from them, and the clothes should be 
rinsed in a dilute alkali to neutralize this effect. 
They should all be used in solution only, and 
should be kept in bottles with rubber stoppers. 

Sulphurous acid gas (S0 2 ), obtained by burn- 
ing sulphur, is also a well-known agent for bleach- 
ing. It will often remove spots which nothing 
else will touch. The amount given off from a 
burning sulphur match will often be sufficient to 
remove from the fingers fruit stains or those made 
by black kid gloves. 

The alkalies which are indispensable are : 

ist. Ammonia, — better that of the druggist than 
the often impure and always weak "household 
ammonia." The strong ammonia is best diluted 
about one half, since it is very volatile, and much 
escapes into the air. 

2d. Potash, which is found at the grocers in 
small cans. - The lye obtained from wood ashes 
owes its caustic and soap-making properties to 
this substance. Potash is corrosive in its action, 
and must be used with discretion. 



148 THE CHEMISTRY OF 

Crystallized sodium carbonate, the sal-soda of 
the grocer, is not, chemically speaking, an alkali, 
but it gives all the effect of one, since the car- 
bonic acid readily gives place to other substances. 

Sal-soda is a very cheap chemical, since it is 
readily manufactured in large quantities, and 
forms the basis of most of the washing powders on 
the market. With grease, it forms a soap which 
is dissolved and carried away. 

3d. Borax is a compound of sodium with boric 
acid, and acts as a mild alkali. It is the safest of 
all the alkalies, and affects colored fabrics less 
than does ammonia. 

Solvents for grease are alcohol, chloroform, 
ether, benzine, naphtha, gasolene — all volatile — 
kerosene and turpentine. Of these chloroform is 
the most costly, and is used chiefly for taking spots 
from delicate silks. Fabrics and colors not in- 
jured by water may be treated by alcohol or 
ether. Benzine, naphtha or gasolene are often 
sold, each under the name of the other. If care is 
taken to prevent the spreading of the ring, they 
can be safely used on any fabric. They do not 
mix with water, and are very inflammable. 

The less volatile solvents are kerosene and tur- 
pentine. Kerosene is a valuable agent in the house- 
hold, and since some of the dealers have provided 
a deodorized quality, it should find an even wider 



COOKING AND CLEANING. 149 

use. The lighter variety is better than the 150 
degree fire test, which is the safe oil for lamps. As 
has been indicated in the preceding pages, the 
housewife will find many uses for this common 
substance. 

On account of the purity and cheapness of kero- 
sene, turpentine is less used than formerly, al- 
though it has its advantages. 

These household chemicals should have their 
own chest or closet, as separate from other bottles 
as is the medicine chest, and especially should they 
be separate from it. Many distressing accidents 
have occurred from swallowing ammonia by mis- 
take. 

In addition to these substances, certain others 
may be kept on hand, if the housewife has sufficient 
chemical knowledge to enable her to detect adul- 
teration in the groceries and other materials which 
she buys. 

A few of these simple tests are given with the 
chemicals needed. 

Directions for Using the Housekeeper's 
Laboratory. 

When directed to make a solution acid or alka- 
line, always test it by means of the litmus paper: — 

Blue turned to red means acid. Red turned to 
blue means alkaline. 



150 THE CHEMISTRY OF 

Only by following the directions can the test be 
relied upon. Under other circumstances than 
those given, the results may mean something else. 

Use the acids in glass or china vessels only. 
Metals may be attacked. Do not touch brass with 
ammonia. 

To test for sulphuric acid or soluble sulphate in 
soda, cream of tartar, baking powder, vinegar, 
sugar or syrup: Add muriatic acid (HC1) to the 
solution (if the insoluble part is sulphate of lime, it 
will dissolve in HC1 on heating), then add barium 
chloride (BaCl 2 ). A heavy white precipitate 
proves the presence of sulphuric acid, either free 
or combined. If the solution is not distinctly acid 
at first, it is not free. 

To test for lime in cream of tartar, baking pow- 
der, sugar or syrup: Make the solution alkaline 
with ammonia and ammonium oxalate. A fine 
white precipitate proves presence of lime. Good 
cream of tartar will dissolve in boiling water, and 
will show only slight cloudiness when the test for 
lime is applied. 

To test for phosphates in cream of tartar or bak- 
ing powder: Make acid by nitric acid (HNO s ), 
and add ammonium molybdate; A fine yellow pre- 
cipitate or yellow color proves presence of phos- 
phates. 

To test for chlorides in soda, baking powder, 



COOKING AND CLEANING. 151 

sugar, syrup or water : Make the solution (a fresh 
portion) acid with nitric acid (HNO s ), and add sil- 
ver nitrate (AgN0 3 ). A white, curdy precipitate 
or a cloudiness indicates chlorides. 

To test for ammonia in baking powder: Add a 
small lump of caustic potash to a strong water 
solution. Red litmus will turn blue in the steam, 
on heating. 

To test for alum in cream of tartar, baking pow- 
der or bread: Prepare a fresh decoction of log- 
wood; add a few drops of this to the solution or 
substance, and render acid by means of acetic acid 
(C 2 H 4 2 ). A yellow color in the acid solution 
proves absence of alum. A bluish or purplish red, 
more or less decided, means more or less alum. 

If the label of a washing powder claims it to be 
something new, and requires that it be used with- 
out soda, as soda injures the clothes, it can be 
tested as follows: Put half a teaspoonful of the 
powder into a tumbler, add a little water, then a 
few drops of muriatic acid. A brisk effervescence 
will prove it to be a carbonate, and if the edge of 
the tumbler is held near the colorless flame of an 
alcohol lamp, the characteristic yellow color of 
sodium will appear and complete the proof. If the 
acid is added, drop by drop, until no more effer- 
vescence occurs, and there remains a greasy scum 
on the surface of the liquid in the tumbler, the 



152 COOKING AND CLEANING. 

compound contains soap as well as sal-soda, for 
the acid unites with the alkali of the soap and sets 
free the grease. 

If some very costly silver polishing powder is 
offered as superior to all other powders, a drop or 
two of muriatic acid will decide whether or not it 
is chalk or whiting, (CaC0 3 ) by the effervescence 
or liberation of the carbonic acid gas. 

Caution! Use a new solution or a fresh por- 
tion of the first one for each new test. This it is 
essential to remember. 

To judge of the quantity of any of the sub- 
stances, it is necessary to have a standard article 
with which to compare the suspected one. Take 
the same quantity of each, and subject each to the 
same tests. A very correct judgment may thus be 
formed. Besides this laboratory there should be 
in every household an emergency case, placed in 
an accessible and well-known cupboard, but out 
of the reach of children. It should be plainly 
labeled and kept stocked with the various solu- 
tions, plasters, ointments, etc., with which the 
house-mother soothes wounded nerves as well as 
bruised noses. 



BOOKS OF REFERENCE. 



Consulted in the Revision of the Chemistry of 
Cooking and Cleaning. 

Foods: Composition and Analysis A. W. Blyth 

Dietetic Value of Bread John Goodfellow 

Food, Manuals of Health Albert J. Bernays 

Food and Its Functions James Knight 

Analysis and Adulteration of Foods James Bell 

Food A. H. Church 

Foods and Feeding Sir Henry Thompson 

The Chemistry of Cookery W. Mattieu Williams 

Chemistry of Wheat, Flour and Bread and Tech- 
nology of Bread Making Wm. Jago 

The Spirit of Cookery J. L. W. Thudichum 

Food in Health and Disease I. Burney Yeo 

Diet in Sickness and Health Mrs. Ernest Hart 

Chemistry and Economy of Food, U. S. Dept. 

Agriculture, Bulletin 21, 1895 W. O. Atwater 

Also Bulletins 28, 29, 31, 35, 37. 
Farmers' Bulletins 34, 42. 

Dietetics Gilman Thompson 

Practical, Sanitary and Economic Cooking 

Mrs. Mary Hinman Abel 

How to Feed Children Louise E. Hogan 

The Science of Nutrition Edward Atkinson 

Food Materials and Their Adulterations 

Ellen H. Richards 



154 BOOKS OF REFERENCE. 

Handbook of Invalid Cooking Mary A. Boland 

The Young Housekeeper Maria Parloa 

Chemie der menschlichen Nahrungs und Genus- 

mittel J. Koenig 

Physiological Chemistry of the Animal Body 

Arthur Gamgee 
A Text-book of Physiological Chemistry. . .Hammarsten 

Chemistry of Daily Life Lassar Cohn 

Organic Chemistry Remsen 

Inorganic Chemistry Remsen 

Dust and Its Dangers T. Mitchell Prudden 

The Story of the Bacteria T. Mitchell Prudden 

The Story of Germ Life Prof. H. W. Conn 

Home Sanitation. .Ellen H. Richards and Marion Talbot 

Household Economics Mrs. Helen Campbell 

How to Drain a House George Waring 

Homes and All About Them E. C. Gardner 

The House that Jill Built E. C. Gardner 

From Attic to Cellar Mrs. Eliz. F. Holt 

The Art of Laundry Work Florence R. Jack 

The Micro-Organisms of Fermentation 

Alfred Jorgensen 

Our Secret Friends and Foes Percy Frankland 

Housework and Domestic Economy. .. .M. E. Haddon 

Emergencies and How to Meet Them J. W. Howe 

Manual of Lessons on Domestic Economy. .. .H. Major 

Handbook of Sanitary Information 

Roger S. Tracy, M. D. 
The Food Products of the World... Dr. Mary E. Green 

Le Pain et la Panification Leon Boutroux 

Eating and Drinking Albert H. Hoy, M. D. 

Text-Book of Am. Physiology Prof. Wm. Howell 



INDEX. 



Absorbents of grease, ioo, 101 
Acids, 16, 17, 21, 41, 146 

Acetic, 38 

Butyric, 35 

for iron stains, 132 

Mineral, 21. 

Muriatic or Hydrochloric, 13, 17, 
19, 41, 132, 146 

Oxalic, 116, 147 

Stearic, 43 

Tannic, 50 
Air, a substance, 85 

as food, 67 

not the agent of change, 73 

pollution of, 84 

pure, 83 
Albumin, 49 
Albuminoids, 50 
Alcohol, 30, 36 
Alcohol, as solvent, 102, no, 148 

product of fermentation, 30, 36, 38 
Alkalies, caustic, 89, in 

Volatile, 89 
Alkali metals, 88 
Aluminum, 117 
Ammonia, 89 

uses of, 73, 93, 102, 125, 139, 147 
Ammonium, 88, 89 
Animal body, a living machine, 47 

repair of, 48 
Art of cooking, 56, 62 
Atoms, 5, 11 
Atomic weight, 10, 11 

of hydrogen, 14 

Bacteria, 36, 39, 74, 76, 77, 81 

action x>f in disease, 80 

as flavor producers, 62 

food of, 81 

spores of, 75 
Bacteriology of bread-making, 36 
Baking powder, 23 
Beans, 52, 64 
Beer, 29 

Benzine, 98, 102, 148 
Biscuits, 39 



Bleaching, 134, 135 

Bleaching powder, 135 (See chloride 

of lime and Javelle Water) 
Blinds, 82 

Blood-stains, 106, 129 
Blotting paper for ink, 108 
Bluing, 133, 134 
Books for reference, 153 
Borax, 125, 128, 137, 139, 148 
Brass, 116 
Bread-making, chemical reactions in 

29, 30, 36 
Bread, as food, 33 

crust, 39 

fermented, 36 

flavor in, 39 

ideal, 34 

home made, 37 

leavened, 35 

object of baking, 38 

reason for kneading, 

temperature of baking, 37, 38, 39, 34 » 
of fermentation, 37 

stale, 39 
Butter, 43 
Butyric acid, 35 

cream of tartar, 41, 42 

Caesium, 88 

Calcium hypochlorite, 128 

Calories, 47 

Cane sugar, 28, 29 

Carbohydrates, 26, 44, 63 

Carbon dioxide (carbonic acid gas), 

16, 17, 18, 19,20, 25,30, 36, 37 
method of obtaining, 40 
Casein, 52 
Caustic alkalies, 89 
Cayenne pepper, 59 
Cellulose, 27 

Cheesecloth for cleaning, 93 
Chemical arithmetic, 18, 21 
Chemical change, 3, 10, 28 

produces heat, 25 
Chemical elements, tables of, 15, 16, 

17 



156 



INDEX. 



Chemical elements, laws of combina- 
tion, 19 

equations, 18, 21 
Chemical Laws, 10, 13 
Chemical reaction, 21, 25 

reactions in bread and beer making, 

36 
Chemical Symbols, n 
Chemicals for household use, 145 
Chloride of lime, 126, 127, 128, 129, 

, 147 
Chlorine, 13 
Chloroform, 102, 148 
Cleaning of brass, 116 

fabrics, 97, 98 

glass, 96 

paint, 93 

silver, in, 116 

wood, 90, 91, 92, 93 

powders, 113 

problems of, 90 

processes of, 88, 90 
Cleanness, ideal and sanitary, 142 

of school houses, 144 

personal, 143 

philosophy of, 82, 85 

public, 144 
Cocoa and coffee stains, 127, 128 
Collagen, 50 

Colors, setting of, 140, 146 
Combustion of food, 25, 26 

products of, 84 
Condiments, 56, 58, 59 
Consumption, 83 
Conversion of starch, 28, 30 
Cooking, American, 58 

art of, 56, 57, 62 

chemistry of, 58 

discretion in, 62 

economy in, 60 

effect of, 54 

fats, 46 

nitrogenous food, 50, 53 

object of, 53 

starch, 32 

vegetables, 60 
Copper, 115, 116 
Cottonseed oil, 43 
Cream of tartar, 23, 41, 42 

Decomposition, 64 

Definite proportions, laws of, 19 

Development of flavor, 56 

Dextrose, 29 

Diatase, 29 

Diet, 63, 65 



Diet, fat in, 45 
Dietaries, 68, 69 
Digestion, 28, 61, 63, 66 

of fats, 44 

is solution, 28 
Dirt, definition of, 78 

prevention of, 98 
Disease, cause of, 80 

prevention of, 79 
Dish cloths and towels, 140 
Dust, 71, 72,73, 75,87, 88 

composed of, 77 

germs, 80 

in air, 72, 76 

meteoric, 73 

on fabrics, 97, 98 

on wood, 92 

spots, 103 

Economy in cooking, 60 

of mixed diet, 65 
Effect of cooking, 54 

of condiments, 58 
Eggs, 51 

Elements, Chemical, 9 
Energy, sources of, 44 

mechanical unit of, 47 
Ether, 102, 148 

Exchange value, 14, 15, 17, *o 
Expansion of gases, 6 

of water, 40 

Fabrics, 97, 98 

Fat, effect of high temperature on, 46 

digestion of, 44 

in diet, 44 
Fats, 24, 43, 45, 55, 88 
Fermentation, 33, 39 
Finish of woods, 90 
Flavor, 46, 56, 57, 58, 60 
Flour, use of in bread, 39 
Food, office of, 24, 69 

water and air as, 68 
Forces causing change, 4 
Fruit stains, 126, 137 
Fuel in body, 47 
Fungi, 74 

Gases, 3 

Gasolene, 148 

Germs, 74, 80, 81 

Glass, 96 

Glucose, 29 

Gluten, 52 

Grass stains, T29 

Grease, 87, 88, 100, 101, 102, 104, 135 



INDEX. 



161 



Grease, on wood, 103 

solvents for, 91 
Groups of elements, 20 
Growth, nitrogenous food required 

for, 48 
Gums, 24 

Heat produced by chemical change, 

24 
source of in animals, 25 
Housekeeper's laboratory, directions 

for using, 149-152 
Hydrochloric acid, (see muriatic) 
Hydrogen, 9, 27, 44 

Ideal bread, 34 
Indigo, 133 

Inflammable substances, 98 
Ink indelible, 109 

stains, 107, 108, 131 
Inoculation, 82 

Iron rust, removal of, ir7, 131, 132, 
MS 

Javelle Water, 126, 127, 128, 129, 130 
Jewelry, 115 

Kerosene, 91,92, 96, in, 116, 117, 131, 

141, 148, 149 
Kitchen utensils, 117 

Laboratory, housekeeper's, 149 
Lard, 43 

Laundry, 118-142 
Law of Combination, 13 

definite proportion, 19 

multiple proportion, 19 
Leather, 94 
Leaven, 35 
Legumin, 52 
Lentils, 65 
Levulose, 29 
Lithium, 88, 89 

Marble, 95, 109 

Matter, changes in, 1, 2, 3, 4 

definition of, 1 

forms of, 3 

states of, 5 
Medicine stains, 127 
Metals, 95, in, 116 
Mildew, 130 
Milk stains, 129 
Mineral acids, 21 
Mixed diet, 65 
Molds, 74, 77, 79 



Molecular weight, n 
Molecules, 5, 6, n 
Mucous stains, 129 
Muriatic acid, 41 

Naphtha, 148 
Nature's scavengers, 78 
Nickel, 117 
Nitrogen, 48 

Nitrogenous food, 47, 49,68 
cooking of, 50, 55 

Oils, 43, 45, 88, 92 
Oil finish, 91 
Oil Stains, 130 
Olive Oil, 44, 45 
Oxalic acid, 147 
Ox-gall, 103 
Oxygen, g, 26, 43 
Oysters, 51 

Paint, 93, 104 

Paper, 94 

Pastry, 54 

Pathogenic germs, 81 

Pearlash, 

Pepsin, 64 

Peptones, 64 

Physical change, 2, 3 

Pitch, 105 

Plated silver ware, 112 
cyanide, 113 

Plumbing, care of, 141 

Porcelain, 96, no 

Potash, 103, 122, 123, 147 

Potassium, 88 

Preparation for food, of starch, sugar 
and fat, 24 

Prevention, 80, 98 

Principles of diet, 

Products of decomposition, 64 

Proportion of nitrogenous food re- 
quired, 68 

Pumice, 95 

Rations, 69 

Reference books, 153 

Removal of dust, spots and stains, 87 

Restoring color, 97 

Rubidium, 88 

Rust of iron, 117 

Saliva, 63 

Sal-soda, 148 

Salt, 7, 41, 42 

School house sanitation, 143 



158 



INDEX. 



Seasonable diet, 65 

Serving, 62 

Shellac, dissolved by alcohol, in 

Silver, cleaning of, in, 113, 114,115 

nitrate, 

polish, 113, 114 
Silver-ware, 112, 115 
Soap, 89, 120, 122, 124, 137, 139 

bark, 121 

berry tree, 121 
Soda, 7, 42, 122, 124 
Soda ash, 17, 123, 124 
Sodium, 87 

Sodium carbonate, 148 
Solution, 6, 7, 28, 50, 81 
Solvents, 78, 91, 101, 102, 106, 148 
Source of energy, 44 
Spores, 75 
Spots, 100, 118 

Stains, 100, 106, 118, 126, 127, 128 
Starch, 24, 27, 28, 29, 30, 31 

cooking of 32, 55,61 
Stearic acid, 43 
Stimulants, 60 
Stoves, care of, 117 
Sugar, 2, 24, 27, 29 

cane, 28 

fruit, 28 

milk, 27, 28 
Suet, 43 
Sulphur fumes, 127, 147 



Sunlight, 82, 83, 84, 85 
Symbols, 11, 12, 
Syrups, 7 

Tables, 15, 16, 17, 21, 23 

Tannin, 128 
Tarnish, 100, 101 
Tea stains, 127, 128 
Temperature, 26, 46, 49, 52, 53 
Turpentine, 91, 102, 103, 126, 148 

Ultramarine, 133, 134 
Unit of value, 14 
Utensils, Kitchen, 117 

Valence, 14 
Varnish, 91, 105 
Vegetables, 60 

Wall paper, 94 
Washing-Soda, 124, 125 
Water, 18, 118, 119, 120 

as food, 67 

hard, 119, 120 
Wax, 91, 105 
Whiting, 114 
Wine stains, 121 
Wood finish, 90, 91, 92 
Woolens, washing of, 139 

Yeast, 33, 35, 36, 37, 38, 74, 78 



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